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It’s time for decentralized social apps to take over It’s a rare occurrence when people across all generations and sides of the political spectrum agree. One of these things is on the invasiveness and control of big tech. Regardless of your opinion on content moderation or censorship, we can all agree that the power social corporations like Facebook, Twitter and Youtube have over our personal data and online identities is alarming. Every time we provide our information or publish content onto these centralized platforms, that unique piece of data no longer belongs to us. We are given a false sense of ownership over our tweets, videos or blogs, when in reality, the moment we click publish, we give up control and send it to a centralized server owned by one large entity. The challenge is that the growing skepticism of centralized tech giants is also growing in congruence with our reliance on their platforms. The market is ripe for an alternative option from the main social platforms, one that doesn't place corporate monetization first, but the user at the center of it. Why we need a new social platform There are two main issues with traditional social media platforms: censorship and unfair monetization. Despite the constitutional right to free speech, censorship occurs on social platforms because it is technically a private forum owned by an entity. This means that the corporate owner has the right to moderate the feed, remove content that doesn’t fit under their rules, and in the worst-case scenario, block user access to their accounts. When combined with black box algorithms determining what content users see and putting all this power in the hands of even individual people, it’s already been shown to even affect elections around the world so the risks are not restricted on an individual’s level. The other issue is caused by the advertising-driven revenue models of web2 apps, where even one third of the posts can be paid ads. Yet often none of the revenue is shared with the content creators who are then forced to make their own advertorial posts to get compensated or in case of, for example, Reddit moderators are “paid” in Karma points with no monetary value. . So despite how it may appear on social media, the large majority of content creators aren’t actually making a decent living wage on these platforms. How do we solve the problem? To understand the solution, we need to get to the root of the problem and unpack how these centralized networks operate. All social media platforms use some type of social graph - an intricate model that maps out all users and how they relate to one another. Traditional big tech companies own and control the social network and store it in their private data servers. This approach means our online lives are fragmented in separate walled gardens where platforms decide who sees your posts, sometimes arbitrarily delete some of them, or can anytime kick you out and wipe your entire social network for one mishap. With blockchain technology, it is now possible to decentralize the social graph where, instead of corporations, each user owns their profile and all the posts and relationships in it.. Lens Protocol, the brainchild of Aave, is an open-source social graph that empowers any developer to build and launch a blockchain-based social platform. On Lens, your profile, and relationships with any other profiles are represented as NFTs and stored on-chain. These profiles are interoperable across all Lens dApps and stored in your own crypto wallet instead of a centralized platform.. Your profile and content is owned and operated by you and if you’re unhappy with how one app treats you, you can seamlessly move to others without losing your followers. With users in control, this approach requires a genuinely user-focused approach from the apps built for the next generation of social. Phaver, the first mobile app released on Lens, is tackling this with a token economy that is geared to share the success with the content creators, curators and moderators who help to build and maintain the high-quality content feed that any successful social app needs. Creating value for the community is rewarded with tokens while they can be spent to boost content visibility, subscribe to premium content or, for example, a fully ad-free experience, creating a two-sided liquid market that rewards not only the largest influencers, but all parties who help to improve the experience. Furthermore, the governance tokens earned by the best users can also be used to vote on any future decisions, making sure things like content guidelines and algorithms are built for the community instead of the advertisers. Where do we go from here? The social media industry is ready for disruption. Elon Musk recently made the news for his very public remarks on transforming Twitter’s censorship-riddled policies by making a $44 billion acquisition offer. Former POTUS, Donald Trump started his own uncensored social app after falling victim to Twitter’s account banning. All these prominent figures are racing to build a solution that will challenge traditional social platforms. What they fail to realize is that winning doesn’t mean owning and controlling a new platform under their rules. True disruption will happen when power and control are given to the people. Social dApps like Phaver are paving the way for a better digital future that is ethical and empowering for people and we’re ready for it.

Millennials Need Decentralized Social Media - Here's Why

Los millennials necesitan redes sociales descentralizadas: este es el motivo

La génération Y a besoin de médias sociaux décentralisés - Voici pourquoi

मिलेनियल्स को विकेन्द्रीकृत सोशल मीडिया की आवश्यकता है - यहाँ पर क्यों

ミレニアル世代には分散型ソーシャル メディアが必要 - その理由

A geração do milênio precisa de mídia social descentralizada - eis o porquê

Millennials cần phương tiện truyền thông xã hội phi tập trung - Đây là lý do tại sao

千禧一代需要去中心化的社交媒体——这就是为什么

The HackerNoon editorial team has launched this interview series with women in tech to celebrate their achievements and share their struggles. We need more women in technology, and by sharing stories, we can encourage many girls to follow their dreams. Share your story today ! #Tell us about yourself! My name is Regina Sadykova, I am a serial entrepreneur. My key competence is PR and marketing.  As a former journalist, I love to tell stories and explain complicated stuff in a simple way. Currently, I work with  Crypto Funds, NFT, and Web3 companies. #Why did you choose this field in the first place? While I started as a journalist covering tech and Venture Capital back in 2010, my career path led me to a PR role as companies kept requesting me to ‘write another article’ and provide focused coverage. Sometimes people confuse journalists with their publicists, but in my case, the referrals and requests continued over the years from a variety of clients and my PR expertise evolved to support them. In 2016, reflecting what was transpiring in the startup economy globally,  most of my tech clients had migrated to having some involvement in Blockchain or Crypto. I realized that to be the beginning of an entirely new era in tech, so I had to learn a lot of new things: crypto-trading, mining, holding, forks, ICOs, staking, farming etc., but it was exciting and informative. PR in crypto is not just writing or pitching; it requires one to be constantly learning as the industry continues to rapidly evolve. I also love to ‘have skin in the game’, risk my own assets and trade NFTs and participate in ICOs. I have been referred to as a ‘Crypto PR Og’, a badge I wear with pride. #What tech are you most excited/passionate about right now and why? At the moment, I am thrilled about digital fashion. As a fashionista, the idea of having endless clothes without having an endless walk-in closet is exciting. Given the size of the market and having previewed some of the innovations on the way, I believe digital fashion will make a meaningful impact on the industry. DressX, my friend Daria Shapovalova’s startup, is a great example of an innovative startup that will help shape the future of digital fashion. I am also intrigued by digital humans. It started with digital influencers like Lil Miquela (@lilmiquela) and I believe you will see more innovations on the ‘virtual influencer’ front soon. Lastly, I love to work with Layer 1 projects, because leaders in this space are focused on upending the status quo and bringing efficiency and transparency to the rapidly evolving industry. I very much admire the ambitions of Solana, Algorand, and other ecosystem creators. #What are you most worried about right now and why? Mental health! We sometimes underestimate the complexity of our daily digital lives; from consuming and processing a vast volume and variety of data from multiple devices while living thru the literal evolution of systems, it can all be a bit overwhelming sometimes. The advent of deepfakes is also concerning; this dangerous new phenomenon in AI stands to wreak havoc on many segments of our society. #What are your hobbies and interests outside of tech? Fashion, running, and reading. Also, I enjoy building communities. For example, now we are working on a Silicon Society members club. #Let's talk about breaking the glass ceiling. What were the biggest challenges you faced as a woman in tech, and how did you deal with them? Ironically, early in my career, not being taken seriously actually helped me; as a journalist, some people would share sensitive information with me just because I looked like a naive student who asks silly questions, but I was in fact doing my job – getting access to people and information not necessarily available to everyone. With experience comes confidence, and while I certainly have grown personally and professionally to handle some of the situations unique to women making inroads in traditionally male-dominated industries, I have found tech industry leadership to be accommodating and working towards inclusivity. Segments of the industry are new and evolving at such a rapid pace that companies need the best minds and creative ideas from employees, and diversity and inclusivity will be a competitive advantage. #Any questionable misogynistic story/situation you faced/handled, and you want to share with the HackerNoon Fam? I am not quite sure if it can be considered misogyny, but as a person who organizes satellite events for crypto-companies during major conferences, on many occasions, I have observed the practice of inviting young, attractive women just to keep gender balance at the party. These female guests are usually models or select nightclub wait staff who are just tasked with showing up and looking beautiful. On one hand, there is nothing offensive about it but on the other, I wish there were more women in tech who would meaningfully participate in industry events and not be treated like ornaments to enhance the ambiance. #What was the biggest setback/failure that you faced, and how did you manage it? I lost nearly 10 bitcoins. It was painful but I learned a few life lessons - and some technical ones. #What's your biggest achievement that you're really proud of? I am proud to have always gone over and above for my clients and having delivered more than promised. While I have accomplished much, I believe that my greatest achievements are still to come. #In your opinion, why do we see this huge gender gap in the tech industry, and how can we reduce it? There are several reasons for the tech gender gap, some historic and cultural, and others more nuanced and resulting from poor diversity and recruiting policies. I believe we need to encourage more female students to undertake STEM curricula in schools and to evolve our recruiting practices so that our tech talent is reflective of our population. I am encouraged by meaningful strides made by non-profits, local governments, and tech companies to date, but it will take time for them to materialize in a balanced workforce. #Who is your tech idol? Why? I admire Whitney Wolfe Herd, who co-founded Bumble after she was sexually harassed and discriminated against at her former company, Tinder. As VP of Marketing, Whitney was the youngest executive at Tinder. In the face of adversity and challenges, she didn’t give up and instead evolved the business by creating a more woman-friendly app, which turned into a wonderful business. #Do you have any advice for aspiring girls who want to join the field? Learn every day. The new dress is a nice choice, but investing in crypto can be a smart choice. The wise choice is to invest in yourself and your own education all the time.

Women in Tech: A Woman of Web3

237 Stories To Learn About Innovation

DYNAMOS AND ELECTRIC MOTORS.

How it Works by Archibald Williams is part of the HackerNoon Books Series. You can jump to any chapter in this book . ELECTRICAL APPARATUS. here Chapter V. ELECTRICAL APPARATUS. What is electricity?—Forms of electricity—Magnetism—The permanent magnet—Lines of force—Electro-magnets—The electric bell—The induction coil—The condenser—Transformation of current—Uses of the induction coil. WHAT IS ELECTRICITY? OF the ultimate nature of electricity, as of that of heat and light, we are at present ignorant. But it has been clearly established that all three phenomena are but manifestations of the energy pervading the universe. By means of suitable apparatus one form can be converted into another form. The heat of fuel burnt in a boiler furnace develops mechanical energy in the engine which the boiler feeds with steam. The engine revolves a dynamo, and the electric current thereby generated can be passed through wires to produce mechanical motion, heat, or light. We must remain content, therefore, with assuming that electricity is energy or motion transmitted through the ether from molecule to molecule, or from atom to atom, of matter. Scientific investigation has taught us how to produce it at will, how to harness it to our uses, and how to measure it; but not it is. That question may, perhaps, remain unanswered till the end of human history. A great difficulty attending the explanation of electrical action is this—that, except in one or two cases, no comparison can be established between it and the operation of gases and fluids. When dealing with the steam-engine, any ordinary intelligence soon grasps the principles which govern the use of steam in cylinders or turbines. The diagrams show, it is hoped, quite plainly "how it works." But electricity is elusive, invisible; and the greatest authorities cannot say what goes on at the poles of a magnet or on the surface of an electrified body. Even the existence of "negative" and "positive" electricity is problematical. However, we see the effects, and we know that if one thing is done another thing happens; so that we are at least able to use terms which, while convenient, are not at present controverted by scientific progress. what FORMS OF ELECTRICITY. Rub a vulcanite rod and hold one end near some tiny pieces of paper. They fly to it, stick to it for a time, and then fall off. The rod was electrified—that is, its surface was affected in such a way as to be in a state of molecular strain which the contact of the paper fragments alleviated. By rubbing large surfaces and collecting the electricity in suitable receivers the strain can be made to relieve itself in the form of a violent discharge accompanied by a bright flash. This form of electricity is known as . static Next, place a copper plate and a zinc plate into a jar full of diluted sulphuric acid. If a wire be attached to them a current of electricity is said to along the wire. We must not, however, imagine that anything actually moves along inside the wire, as water, steam, or air, passes through a pipe. Professor Trowbridge says, "No other agency for transmitting power can be stopped by such slight obstacles as electricity. A thin sheet of paper placed across a tube conveying compressed air would be instantly ruptured. It would take a wall of steel at least an inch thick to stand the pressure of steam which is driving a 10,000 horse-power engine. A thin layer of dirt beneath the wheels of an electric car can prevent the current which propels the car from passing to the rail, and then back to the power-house." There would, indeed, be a puncture of the paper if the current had a sufficient voltage, or pressure; yet the fact remains that electricity can be very easily confined to its conductor by means of some insulating or nonconducting envelope. flow current MAGNETISM. The most familiar form of electricity is that known as magnetism. When a bar of steel or iron is magnetized, it is supposed that the molecules in it turn and arrange themselves with all their north-seeking poles towards the one end of the bar, and their south-seeking poles towards the other. If the bar is balanced freely on a pivot, it comes to rest pointing north and south; for, the earth being a huge magnet, its north pole attracts all the north-seeking poles of the molecules, and its south poles the south-seeking poles. (The north- pole of a magnet is marked N., though it is in reality the pole; for unlike poles are mutually attractive, and like poles repellent.) seeking south There are two forms of magnet— and . If steel is magnetized, it remains so; but soft iron loses practically all its magnetism as soon as the cause of magnetization is withdrawn. This is what we should expect; for steel is more closely compacted than iron, and the molecules therefore would be able to turn about more easily. It is fortunate for us that this is so, since on the rapid magnetization and demagnetization of soft iron depends the action of many of our electrical mechanisms. permanent temporary THE PERMANENT MAGNET. Magnets are either (1) straight, in which case they are called bar magnets; or (2) of horseshoe form, as in Figs. 50 and 51. By bending the magnet the two poles are brought close together, and the attraction of both may be exercised simultaneously on a bar of steel or iron. LINES OF FORCE. In Fig. 50 are seen a number of dotted lines. These are called . If you lay a sheet of paper on a horseshoe magnet and sprinkle it with iron dust, you will at once notice how the particles arrange themselves in curves similar in shape to those shown in the illustration. It is supposed (it cannot be ) that magnetic force streams away from the N. pole and describes a circular course through the air back to the S. pole. The same remark applies to the bar magnet. lines of magnetic force proved ELECTRICAL MAGNETS. If an insulated wire is wound round and round a steel or iron bar from end to end, and has its ends connected to the terminals of an electric battery, current rotates round the bar, and the bar is magnetized. By increasing the strength and volume of the current, and multiplying the number of turns of wire, the attractive force of the magnet is increased. Now disconnect the wires from the battery. If of iron, the magnet at once loses its attractive force; but if of steel, it retains it in part. Instead of a simple horseshoe-shaped bar, two shorter bars riveted into a plate are generally used for electromagnets of this type. Coils of wire are wound round each bar, and connected so as to form one continuous whole; but the wire of one coil is wound in the direction opposite to that of the other. The free end of each goes to a battery terminal. In Fig. 51 you will notice that some of the "lines of force" are deflected through the iron bar a. They pass more easily through iron than through air; and will choose iron by preference. The attraction exercised by a magnet on iron may be due to the effort of the lines of force to shorten their paths. It is evident that the closer a comes to the poles of the magnet the less will be the distance to be travelled from one pole to the bar, along it, and back to the other pole. Having now considered electricity in three of its forms—static, current, and rotatory—we will pass to some of its applications. THE ELECTRIC BELL. In Fig. 52 we have a diagrammatic view of an electric bell and current. When the bell-push is pressed in, current flows from the battery to terminal t1, round the electro-magnet m, through the pillar p and flat steel springs s and b, through the platinum-pointed screw, and back to the battery through the push. The circulation of current magnetizes m, which attracts the iron armature a attached to the spring s, and draws the hammer h towards the gong. Just before the stroke occurs, the spring b leaves the tip of the screw, and the circuit is broken, so that the magnet no longer attracts. h is carried by its momentum against the gong, and is withdrawn by the spring, until b once more makes contact, and the magnet is re-excited. The hammer vibrations recur many times a second as long as the push is pressed in. The electric bell is used for so many purposes that they cannot all be noted. It plays an especially important part in telephonic installations to draw the attention of the subscribers, forms an item in automatic fire and burglar alarms, and is a necessary adjunct of railway signalling cabins. THE INDUCTION OR RUHMKORFF COIL. Reference was made in connection with the electrical ignition of internal-combustion engines ( ) to the . This is a device for increasing the , or pressure, of a current. The two-cell accumulator carried in a motor car gives a voltage (otherwise called electro-motive force = E.M.F.) of 4·4 volts. If you attach a wire to one terminal of the accumulator and brush the loose end rapidly across the other terminal, you will notice that a bright spark passes between the wire and the terminal. In reality there are two sparks, one when they touch, and another when they separate, but they occur so closely together that the eye cannot separate the two impressions. A spark of this kind would not be sufficiently hot to ignite a charge in a motor cylinder, and a spark from the induction coil is therefore used. p. 101 induction coil voltage We give a sketch of the induction coil in Fig. 53. It consists of a core of soft iron wires round which is wound a layer of coarse insulated wire, denoted by the thick line. One end of the winding of this coil is attached to the battery, the other to the base of a hammer, h, vibrating between the end of the core and a screw, s, passing through an upright, t, connected with the other terminal of the battery. The action of the hammer is precisely the same as that of the armature of an electric bell. Outside the primary coil are wound many turns of a much finer wire completely insulated from the primary coil. The ends of this coil are attached to the objects (in the case of a motor car, the insulated wire of the sparking-plug and a wire projecting from its outer iron casing) between which a spark has to pass. As soon as h touches s the circuit is completed. The core becomes a powerful magnet with external lines of force passing from one pole to the other over and among the turns of the secondary coil. h is almost instantaneously attracted by the core, and the break occurs. The lines of force now (at least so it is supposed) sink into the core, cutting through the turns of the "secondary," and causing a powerful current to flow through them. The greater the number of turns, the greater the number of times the lines of force are cut, and the stronger is the current. If sufficiently intense, it jumps any gap in the secondary circuit, heating the intermediate air to a state of incandescence. primary secondary THE CONDENSER. The sudden parting of h and s would produce strong sparking across the gap between them if it were not for the condenser, which consists of a number of tinfoil sheets separated by layers of paraffined paper. All the "odd" sheets are connected with t, all the "even" with t1. Now, the more rapid the extinction of magnetism in the core after "break" of the primary circuit, the more rapidly will the lines of force collapse, and the more intense will be the induced current in the secondary coil. The condenser diminishes the period of extinction very greatly, while lengthening the period of magnetization after the "make" of the primary current, and so decreasing the strength of the reverse current. TRANSFORMATION OF CURRENT. The difference in the voltage of the primary and secondary currents depends on the length of the windings. If there are 100 turns of wire in the primary, and 100,000 turns in the secondary, the voltage will be increased 1,000 times; so that a 4-volt current is "stepped up" to 4,000 volts. In the largest induction coils the secondary winding absorbs 200–300 miles of wire, and the spark given may be anything up to four feet in length. Such a spark would pierce a glass plate two inches thick. It must not be supposed that an induction coil increases the of current given off by a battery. It merely increases its pressure at the expense of its volume—stores up its energy, as it were, until there is enough to do what a low-tension flow could not effect. A fair comparison would be to picture the energy of the low-tension current as the momentum of a number of small pebbles thrown in succession at a door, say 100 a minute. If you went on pelting the door for hours you might make no impression on it, but if you could knead every 100 pebbles into a single stone, and throw these stones one per minute, you would soon break the door in. amount Any intermittent current can be transformed as regards its intensity. You may either increase its pressure while decreasing its rate of flow, or ; or decrease its pressure and increase its flow. In the case that we have considered, a continuous battery current is rendered intermittent by a mechanical contrivance. But if the current comes from an "alternating" dynamo—that is, is already intermittent—the contact-breaker is not needed. There will be more to say about transformation of current in later paragraphs. amperage USES OF THE INDUCTION COIL. The induction coil is used—(1.) For passing currents through glass tubes almost exhausted of air or containing highly rarefied gases. The luminous effects of these "Geissler" tubes are very beautiful. (2.) For producing the now famous X or Röntgen rays. These rays accompany the light rays given off at the negative terminal (cathode) of a vacuum tube, and are invisible to the eye unless caught on a fluorescent screen, which reduces their rate of vibration sufficiently for the eye to be sensitive to them. The Röntgen rays have the peculiar property of penetrating many substances quite opaque to light, such as metals, stone, wood, etc., and as a consequence have proved of great use to the surgeon in localizing or determining the nature of an internal injury. They also have a deterrent effect upon cancerous growths. (3.) In wireless telegraphy, to cause powerful electric oscillations in the ether. (4.) On motor cars, for igniting the cylinder charges. (5.) For electrical massage of the body. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Archibald Williams (2009). How it Works. Urbana, Illinois: Project Gutenberg. Retrieved https://www.gutenberg.org/cache/epub/28553/pg28553-images.html This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

ELECTRICAL APPARATUS.

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72 Stories To Learn About Tech Trends

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2023 के लिए ब्लॉकचेन में सोशिएबल के 40 अंडर 40 प्रभावशाली व्यक्ति

The Sociable の 2023 年のブロックチェーンにおける 40 歳未満のインフルエンサー 40 人

Os 40 influenciadores com menos de 40 anos do Sociable no Blockchain para 2023

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The Sociable 评选 2023 年区块链领域 40 位 40 岁以下影响者

The Radio Amateur's Hand Book, by A. Frederick Collins is part of . You can jump to any chapter in this book here: . Chapter XIX: The Operation of Vacuum Tube Transmitters HackerNoon’s Book Blog Post series [LINK TO TABLE OF LINK] XIX. THE OPERATION OF VACUUM TUBE TRANSMITTERS The three foregoing chapters explained in detail the design and construction of (1) two kinds of C. W. telegraph transmitters, and (2) two kinds of wireless telephone transmitters, the difference between them being whether they used (A) a direct current, or (B) an alternating current as the initial source of energy. Of course there are other differences between those of like types as, for instance, the apparatus and connections used (a) in the key circuits, and (b) in the microphone circuits. But in all of the transmitters described of whatever type or kind the same fundamental device is used for setting up sustained oscillations and this is the vacuum tube. The Operation of the Vacuum Tube Oscillator.--The operation of the vacuum tube in producing sustained oscillations depends on (1) the action of the tube as a valve in setting up the oscillations in the first place and (2) the action of the grid in amplifying the oscillations thus set up, both of which we explained in . In that chapter it was also pointed out that a very small change in the grid potential causes a corresponding and larger change in the amount of current flowing from the plate to the filament; and that if a vacuum tube is used for the production of oscillations the initial source of current must have a high voltage, in fact the higher the plate voltage the more powerful will be the oscillations. Chapter XIV To understand how oscillations are set up by a vacuum tube when a direct current is applied to it, take a look at the simple circuits shown in Fig. 94. Now when you close the switch the voltage from the battery charges the condenser and keeps it charged until you open it again; the instant you do this the condenser discharges through the circuit which includes it and the inductance coil, and the discharge of a condenser is always oscillatory. Where an oscillator tube is included in the circuits as shown at A and B in Fig. 94, the grid takes the place of the switch and any slight change in the voltage of either the grid or the plate is sufficient to start a train of oscillations going. As these oscillations surge through the tube the positive parts of them flow from the plate to the filament and these carry more of the direct current with them. To make a tube set up powerful oscillations then, it is only necessary that an oscillation circuit shall be provided which will feed part of the oscillations set up by the tube back to the grid circuit and when this is done the oscillations will keep on being amplified until the tube reaches the limit of its output. The Operation of C. W. Telegraph Transmitters With Direct Current--Short Distance C. W. Transmitter.--In the transmitter shown in the wiring diagram in Fig. 76 the positive part of the 110 volt direct current is carried down from the lamp socket through one side of the panel cut-out, thence through the choke coil and to the plate of the oscillator tube, when the latter is charged to the positive sign. The negative part of the 110 volt direct current then flows down the other wire to the filament so that there is a difference of potential between the plate and the filament of 110 volts. Now when the 6-volt battery current is switched on the filament is heated to brilliancy, and the electrons thrown off by it form a conducting path between it and the plate; the 110 volt current then flows from the latter to the former. Now follow the wiring from the plate over to the blocking condenser, thence to clip 3 of the tuning coil, through the turns of the latter to clip 2 and over to the filament and, when the latter is heated, you have a closed oscillation circuit. The oscillations surging in the latter set up other and like oscillations in the tuning coil between the end of which is connected with the grid, the aerial and the clip 2, and these surge through the circuit formed by this portion of the coil, the grid condenser and the filament; this is the amplifying circuit and it corresponds to the regenerative circuit of a receiving set. When oscillations are set up in it the grid is alternately charged to the positive and negative signs. These reversals of voltage set up stronger and ever stronger oscillations in the plate circuit as before explained. Not only do the oscillations surge in the closed circuits but they run to and fro on the aerial wire when their energy is radiated in the form of electric waves. The oscillations are varied by means of the telegraph key which is placed in the grid circuit as shown in Fig. 76. The Operation of the Key Circuit.--The effect in a C. W. transmitter when a telegraph key is connected in series with a buzzer and a battery and these are shunted around the condenser in the grid circuit, is to rapidly change the wave form of the sustained oscillations, and hence, the length of the waves that are sent out. While no sound can be heard in the headphones at the receiving station so long as the points of the key are not in contact, when they are in contact the oscillations are modulated and sounds are heard in the headphones that correspond to the frequency of the buzzer in the key circuit. The Operation of C. W. Telegraph Transmitters with Direct Current.--The chief differences between the long distance sets which use a direct current, i.e., those described in , and the short distance transmitting sets are that the former use: (1) a motor-generator set for changing the low voltage direct current into high voltage direct current, and (2) a chopper in the key circuit. The way the motor-generator changes the low- into high-voltage current has been explained in . Chapter XVI Chapter XVI The chopper interrupts the oscillations surging through the grid circuit at a frequency that the ear can hear, that is to say, about 800 to 1,000 times per second. When the key is open, of course, the sustained oscillations set up in the circuits will send out continuous waves but when the key is closed these oscillations are broken up and then they send out discontinuous waves. If a heterodyne receiving set, see , is being used at the other end you can dispense with the chopper and the key circuit needed is very much simplified. The operation of key circuits of the latter kind will be described presently. Chapter XV The Operation of C. W. Telegraph Transmitters with Alternating Current--With a Single Oscillator Tube.--Where an oscillator tube telegraph transmitter is operated by a 110 volt alternating current as the initial source of energy, a buzzer, chopper or other interruptor is not needed in the key circuit. This is because oscillations are set up only when the plate is energized with the positive part of the alternating current and this produces an intermittent musical tone in the headphones. Hence this kind of a sending set is called a tone transmitter. Since oscillations are set up only by the positive part or voltage of an alternating current it is clear that, as a matter of fact, this kind of a transmitter does not send out continuous waves and therefore it is not a C. W. transmitter. This is graphically shown by the curve of the wave form of the alternating current and the oscillations that are set up by the positive part of it in Fig. 95. Whenever the positive half of the alternating current energizes the plate then oscillations are set up by the tube and, conversely, when the negative half of the current charges the plate no oscillations are produced. You will also observe that the oscillations set up by the positive part of the current are not of constant amplitude but start at zero the instant the positive part begins to energize the plate and they keep on increasing in amplitude as the current rises in voltage until the latter reaches its maximum; then as it gradually drops again to zero the oscillations decrease proportionately in amplitude with it. Heating the Filament with Alternating Current.--Where an alternating current power transformer is used to develop the necessary plate voltage a second secondary coil is generally provided for heating the filament of the oscillation tube. This is better than a direct current for it adds to the life of the filament. When you use an alternating current to heat the filament keep it at the same voltage rather than at the same amperage (current strength). To do this you need only to use a voltmeter across the filament terminals instead of an ammeter in series with it; then regulate the voltage of the filament with a rheostat. The Operation of C. W. Telegraph Transmitters with Alternating Current--With Two Oscillator Tubes.--By using two oscillator tubes and connecting them up with the power transformer and oscillating circuits as shown in the wiring diagram in Fig. 83 the plates are positively energized alternately with every reversal of the current and, consequently, there is no time period between the ending of the oscillations set up by one tube and the beginning of the oscillations set up by the other tube. In other words these oscillations are sustained but as in the case of those of a single tube, their amplitude rises and falls. This kind of a set is called a full wave rectification transmitter. The waves radiated by this transmitter can be received by either a crystal detector or a plain vacuum-tube detector but the heterodyne receptor will give you better results than either of the foregoing types. The Operation of Wireless Telephone Transmitters with Direct Current--Short Distance Transmitter.--The operation of this short distance wireless telephone transmitter, a wiring diagram of which is shown in Fig. 85 is exactly the same as that of the Direct Current Short Distance C. W. Telegraph Transmitter already explained in this chapter. The only difference in the operation of these sets is the substitution of the microphone transmitter for the telegraph key. The Microphone Transmitter.--The microphone transmitter that is used to vary, or modulate, the sustained oscillations set up by the oscillator tube and circuits is shown in Fig. 84. By referring to the diagram at A in this figure you will readily understand how it operates. When you speak into the mouthpiece the sound waves, which are waves in the air, impinge upon the diaphragm and these set it into vibration--that is, they make it move to and fro. When the diaphragm moves toward the back of the transmitter it forces the carbon granules that are in the cup closer together; this lowers their resistance and allows more current from the battery to flow through them; when the pressure of the air waves is removed from the diaphragm it springs back toward the mouth-piece and the carbon granules loosen up when the resistance offered by them is increased and less current can flow through them. Where the oscillation current in the aerial wire is small the transmitter can be connected directly in series with the latter when the former will surge through it. As you speak into the microphone transmitter its resistance is varied and the current strength of the oscillations is varied accordingly. The Operation of Wireless Telephone Transmitters with Direct Current--Long Distance Transmitters.--In the wireless telephone transmitters for long distance work which were shown and described in the preceding chapter a battery is used to energize the microphone transmitter, and these two elements are connected in series with a microphone modulator. This latter device may be either (1) a telephone induction coil, (2) a microphone transformer, or (3) a magnetic modulator; the first two of these devices step-up the voltage of the battery current and the amplified voltage thus developed is impressed on the oscillations that surge through the closed oscillation circuit or the aerial wire system according to the place where you connect it. The third device works on a different principle and this will be described a little farther along. The Operation of Microphone Modulators--The Induction Coil.--This device is really a miniature transformer, see A in Fig. 86, and its purpose is to change the 6 volt direct current that flows through the microphone into 100 volts alternating current; in turn, this is impressed on the oscillations that are surging in either (1) the grid circuit as shown at A in Fig. 89, and in Fig. 90, (2) the aerial wire system, as shown at B in Fig. 89 and Fig. 93. When the current from the battery flows through the primary coil it magnetizes the soft iron core and as the microphone varies the strength of the current the high voltage alternating currents set up in the secondary coil of the induction coil are likewise varied, when they are impressed upon and modulate the oscillating currents. The Microphone Transformer.--This is an induction coil that is designed especially for wireless telephone modulation. The iron core of this transformer is also of the open magnetic circuit type, see A in Fig. 87, and the ratio of the turns [Footnote: See Chapter VI] of the primary and the secondary coil is such that when the secondary current is impressed upon either the grid circuit or the aerial wire system it controls the oscillations flowing through it with the greatest efficiency. The Magnetic Modulator.--This piece of apparatus is also called a magnetic amplifier. The iron core is formed of very thin plates, or laminations as they are called, and this permits high-frequency oscillations to surge in a coil wound on it. In this transformer, see A in Fig. 88, the current flowing through the microphone varies the magnetic permeability of the soft iron core by the magnetic saturation of the latter. Since the microphone current is absolutely distinct from the oscillating currents surging through the coil of the transformer a very small direct current flowing through a coil on the latter will vary or modulate very large oscillating currents surging through the former. It is shown connected in the aerial wire system at A in Fig. 88, and in Fig. 93. Operation of the Vacuum Tube as a Modulator.--Where a microphone modulator of the induction coil or microphone transformer type is connected in the grid circuit or aerial wire system the modulation is not very effective, but by using a second tube as a modulator, as shown in Fig. 90, an efficient degree of modulation can be had. Now there are two methods by which a vacuum tube can be used as a modulator and these are: (1) by the absorption of the energy of the current set up by the oscillator tube, and (2) by varying the direct current that energizes the plate of the oscillator tube. The first of these two methods is not used because it absorbs the energy of the oscillating current produced by the tube and it is therefore wasteful. The second method is an efficient one, as the direct current is varied before it passes into the oscillator tube. This is sufficient reason for describing only the second method. The voltage of the grid of the modulator tube is varied by the secondary coil of the induction coil or microphone transformer, above described. In this way the modulator tube acts like a variable resistance but it amplifies the variations impressed on the oscillations set up by the oscillator tube. As the magnetic modulator does the same thing a vacuum tube used as a modulator is not needed where the former is employed. For this reason a magnetic modulator is the cheapest in the long run. The Operation of Wireless Telephone Transmitters with Alternating Current.--Where an initial alternating current is used for wireless telephony, the current must be rectified first and then smoothed out before passing into the oscillator tube to be converted into oscillations. Further so that the oscillations will be sustained, two oscillator tubes must be used, and, finally, in order that the oscillations may not vary in amplitude the alternating current must be first changed into direct current by a pair of rectifier vacuum tubes, as shown in Fig. 93. When this is done the plates will be positively charged alternately with every reversal of the current in which case there will be no break in the continuity of the oscillations set up and therefore in the waves that are sent out. The Operation of Rectifier Vacuum Tubes.--The vacuum tube rectifier is simply a two electrode vacuum tube. The way in which it changes a commercial alternating current into pulsating direct current is the same as that in which a two electrode vacuum tube detector changes an oscillating current into pulsating direct currents and this has been explained in detail under the heading of The Operation of a Two Electrode Vacuum Tube Detector in . In the C. W. Telegraph Transmitting Sets described in , the oscillator tubes act as rectifiers as well as oscillators but for wireless telephony the alternating current must be rectified first so that a continuous direct current will result. Chapter XII Chapter XVII The Operation of Reactors and Condensers.--A reactor is a single coil of wire wound on an iron core, see Fig. 90 and A in Fig. 91, and it should preferably have a large inductance. The reactor for the plate and grid circuit of a wireless telephone transmitter where one or more tubes are used as modulators as shown in the wiring diagram in Fig. 90, and the filter reactor shown in Fig. 92, operate in the same way. When an alternating current flows through a coil of wire the reversals of the current set up a counter electromotive force in it which opposes, that is reacts, on the current, and the higher the frequency of the current the greater will be the reactance. When the positive half of an alternating current is made to flow through a large resistance the current is smoothed out but at the same time a large amount of its energy is used up in producing heat. But when the positive half of an alternating current is made to flow through a large inductance it acts like a large resistance as before and likewise smooths out the current, but none of its energy is wasted in heat and so a coil having a large inductance, which is called an inductive reactance, or just reactor for short, is used to smooth out, or filter, the alternating current after it has been changed into a pulsating direct current by the rectifier tubes. A condenser also has a reactance effect on an alternating current but different from an induction coil the lower the frequency the greater will be the reactance. For this reason both a filter reactor and filter condensers are used to smooth out the pulsating direct currents. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Collins, A. Frederick. 2002. The Radio Amateur's Hand Book. Urbana, Illinois: Project Gutenberg. Retrieved April 2022, from https://www.gutenberg.org/files/6934/6934-h/6934-h.htm#chap19 This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever.  You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Dissecting Vacuum Tube Transmitters

The Last Days of Marcus Karenin

Chapter XVIII: The Pirate Planet 

Astounding Stories of Super-Science, July 1930, by Astounding Stories is part of HackerNoon’s Book Blog Post series. You can jump to any chapter in this book here . VOL. III, No. 1: The Power and the Glory Astounding Stories of Super - Science, July 1930: VOL. III, No. 1 - The Power and the Glory By Charles W. Diffin "And I would have been the greatest man in the world." Sadly, sternly, the old professor reveals to his brilliant pupil the greater path to glory. THERE were papers on the desk, a litter of papers scrawled over, in the careless writing of indifferent students, with the symbols of chemistry and long mathematical computations. The man at the desk pushed them aside to rest his lean, lined face on one thin hand. The other arm, ending at the wrist, was on the desk before him. Students of a great university had long since ceased to speculate about the missing hand. The result of an experiment, they knew—a hand that was a mass of lifeless cells, amputated quickly that the living arm might be saved—but that was some several years ago, ancient history to those who came and went through Professor Eddinger's class room. And now Professor Eddinger was weary—weary and old, he told himself—as he closed his eyes to shut out the sight of the interminable papers and the stubby wrist that had ended forever his experiments and the delicate manipulations which only he could do. He reached slowly for a buzzing phone, but his eyes brightened at the voice that came to him. "I've got it—I've got it!" The words were almost incoherent. "This is Avery, Professor—Avery! You must come at once. You will share in it; I owe it all to you ... you will be the first to see ... I am sending a taxi for you—" Professor Eddinger's tired eyes crinkled to a smile. Enthusiasm like this was rare among his youngsters. But Avery—with the face of a poet, a dreamer's eyes and the mind of a scientist—good boy, Avery!—a long time since he had seen him—had him in his own laboratory for two years.... "What's this all about?" he asked. "No—no!" said a voice; "I can't tell you—it is too big—greater than the induction motor—greater than the electric light—it is the greatest thing in the world. The taxi should be there now—you must come—" A knock at the office door where a voice said, "Car for Professor Eddinger," confirmed the excited words. "I'll come," said the Professor, "right away." HE pondered, as the car whirled him across the city, on what this greatest thing in the world might be. And he hoped with gentle skepticism that the enthusiasm was warranted. A young man opened the car door as they stopped. His face was flushed, Eddinger noted, hair pushed back in disarray, his shirt torn open at the throat. "Wait here," he told the driver and took the Professor by the arm to hurry him into a dilapidated building. "Not much of a laboratory," he said, "but we'll have better, you and I; we'll have better—" The room seemed bare with its meager equipment, but it was neat, as became the best student of Professor Eddinger. Rows of reagent bottles stood on the shelves, but the tables were a litter of misplaced instruments and broken glassware where trembling hands had fumbled in heedless excitement. "Glad to see you again, Avery." The gentle voice of Professor Eddinger had lost its tired tone. "It's been two years you've been working, I judge. Now what is this great discovery, boy? What have you found?" The younger man, in whose face the color came and went, and whose eyes were shining from dark hollows that marked long days and sleepless nights, still clung to the other's arm. "It's real," he said; "it's great! It means fortune and fame, and you're in on that, Professor. The old master," he said and clapped a hand affectionately upon a thin shoulder; "I owe it all to you. And now I have—I have learned.... No, you shall see for yourself. Wait—" HE crossed quickly to a table. On it was an apparatus; the eyes of the older man widened as he saw it. It was intricate—a maze of tubing. There was a glass bulb above—the generator of a cathode ray, obviously—and electro-magnets below and on each side. Beneath was a crude sphere of heavy lead—a retort, it might be—and from this there passed two massive, insulated cables. The understanding eyes of the Professor followed them, one to a terminal on a great insulating block upon the floor, the other to a similarly protected terminal of carbon some feet above it in the air. The trembling fingers of the young man made some few adjustments, then he left the instrument to take his place by an electric switch. "Stand back," he warned, and closed the switch. There was a gentle hissing from within glass tubes, the faint glow of a blue-green light. And that was all, until—with a crash like the ripping crackle of lightning, a white flame arced between the terminals of the heavy cables. It hissed ceaselessly through the air where now the tang of ozone was apparent. The carbon blocks glowed with a brilliant incandescence when the flame ceased with the motion of a hand where Avery pulled a switch. The man's voice was quiet now. "You do not know, yet, what you have seen, but there was a tremendous potential there—an amperage I can't measure with my limited facilities." He waved a deprecating hand about the ill-furnished laboratory. "But you have seen—" His voice trembled and failed at the forming of the words. "—The disintegration of the atom," said Professor Eddinger quietly, "and the release of power unlimited. Did you use thorium?" he inquired. The other looked at him in amazement. Then: "I should have known you would understand," he said humbly. "And you know what it means"—again his voice rose—"power without end to do the work of the world—great vessels driven a lifetime on a mere ounce of matter—a revolution in transportation—in living...." He paused. "The liberation of mankind," he added, and his voice was reverent. "This will do the work of the world: it will make a new heaven and a new earth! Oh, I have dreamed dreams," he exclaimed, "I have seen visions. And it has been given to me—me!—to liberate man from the curse of Adam ... the sweat of his brow.... I can't realize it even yet. I—I am not worthy...." HE raised his eyes slowly in the silence to gaze in wondering astonishment at the older man. There was no answering light, no exaltation on the lined face. Only sadness in the tired eyes that looked at him and through him as if focused upon something in a dim future—or past. "Don't you see?" asked the wondering man. "The freedom of men—the liberation of a race. No more poverty, no endless, grinding labor." His young eyes, too, were looking into the future, a future of blinding light. "Culture," he said, "instead of heart-breaking toil, a chance to grow mentally, spiritually; it is another world, a new life—" And again he asked: "Surely, you see?" "I see," said the other; "I see—plainly." "The new world," said Avery. "It—it dazzles me; it rings like music in my ears." "I see no new world," was the slow response. The young face was plainly perplexed. "Don't you believe?" he stammered. "After you have seen ... I thought you would have the vision, would help me emancipate the world, save it—" His voice failed. "Men have a way of crucifying their saviors," said the tired voice. The inventor was suddenly indignant. "You are blind," he said harshly; "it is too big for you. And I would have had you stand beside me in the great work.... I shall announce it alone.... There will be laboratories—enormous!—and factories. My invention will be perfected, simplified, compressed. A generator will be made—thousands of horsepower to do the work of a city, free thousands of men—made so small you can hold it in one hand." The sensitive face was proudly alight, proud and a trifle arrogant. The exaltation of his coming power was strong upon him. "Yes," said Professor Eddinger, "in one hand." And he raised his right arm that he might see where the end of a sleeve was empty. "I am sorry," said the inventor abruptly; "I didn't mean ... but you will excuse me now; there is so much to be done—" But the thin figure of Professor Eddinger had crossed to the far table to examine the apparatus there. "Crude," he said beneath his breath, "crude—but efficient!" IN the silence a rat had appeared in the distant corner. The Professor nodded as he saw it. The animal stopped as the man's eyes came upon it; then sat squirrellike on one of the shelves as it ate a crumb of food. Some morsel from a hurried lunch of Avery's, the Professor reflected—poor Avery! Yes, there was much to be done. He spoke as much to himself as to the man who was now beside him. "It enters here," he said and peered downward toward the lead bulb. He placed a finger on the side of the metal. "About here, I should think.... Have you a drill? And a bit of quartz?" The inventor's eyes were puzzled, but the assurance of his old instructor claimed obedience. He produced a small drill and a fragment like broken glass. And he started visibly as the one hand worked awkwardly to make a small hole in the side of the lead. But he withdrew his own restraining hand, and he watched in mystified silence while the quartz was fitted to make a tiny window and the thin figure stooped to sight as if aiming the opening toward a far corner where a brown rat sat upright in earnest munching of a dry crust. The Professor drew Avery with him as he retreated noiselessly from the instrument. "Will you close the switch," he whispered. The young man hesitated, bewildered, at this unexpected demonstration, and the Professor himself reached with his one hand for the black lever. Again the arc crashed into life, to hold for a brief instant until Professor Eddinger opened the switch. "Well," demanded Avery, "what's all the show? Do you think you are teaching me anything—about my own instrument?" There was hurt pride and jealous resentment in his voice. "See," said Professor Eddinger quietly. And his one thin hand pointed to a far shelf, where, in the shadow, was a huddle of brown fur and a bit of crust. It fell as they watched, and the "plop" of the soft body upon the floor sounded loud in the silent room. "The law of compensation," said Professor Eddinger. "Two sides to the medal! Darkness and light—good and evil—life ... and death!" THE young man was stammering. "What do you mean?—a death ray evolved?" And: "What of it?" he demanded; "what of it? What's that got to do with it?" "A death ray," the other agreed. "You have dreamed, Avery—one must in order to create—but it is only a dream. You dreamed of life—a fuller life—for the world, but you would have given them, as you have just seen, death." The face of Avery was white as wax; his eyes glared savagely from dark hollows. "A rat!" he protested. "You have killed a rat ... and you say—you say—" He raised one trembling hand to his lips to hold them from forming the unspeakable words. "A rat," said the Professor—"or a man ... or a million men." "We will control it." "All men will have it—the best and the worst ... and there is no defence." "It will free the world—" "It will destroy it." "No!"—and the white-faced man was shouting now—"you don't understand—you can't see—" The lean figure of the scientist straightened to its full height. His eyes met those of the younger man, silent now before him, but Avery knew the eyes never saw him; they were looking far off, following the wings of thought. In the stillness the man's words came harsh and commanding— "Do you see the cities," he said, "crumbling to ruins under the cold stars? The fields? They are rank with wild growth, torn and gullied by the waters; a desolate land where animals prowl. And the people—the people!—wandering bands, lower, as the years drag on, than the beasts themselves; the children dying, forgotten, in the forgotten lands; a people to whom the progress of our civilization is one with the ages past, for whom there is again the slow, toiling road toward the light. "And somewhere, perhaps, a conquering race, the most brutal and callous of mankind, rioting in their sense of power and dragging themselves down to oblivion...." HIS gaze came slowly back to the room and the figure of the man still fighting for his dream. "They would not," said Avery hoarsely; "they'd use it for good." "Would they?" asked Professor Eddinger. He spoke simply as one stating simple facts. "I love my fellow men," he said, "and I killed them in thousands in the last war—I, and my science, and my poison gas." The figure of Avery slumped suddenly upon a chair; his face was buried in his hands. "And I would have been," he groaned, "the greatest man in the world." "You shall be greater," said the Professor, "though only we shall know it—you and I.... You will save the world—from itself." The figure, bowed and sunken in the chair, made no move; the man was heedless of the kindly hand upon his shoulder. His voice, when he spoke, was that of one afar off, speaking out of a great loneliness. "You don't understand," he said dully; "you can't—" But Professor Eddinger, a cog in the wheels of a great educational machine, glanced at the watch on his wrist. Again his thin shoulders were stooped, his voice tired. "My classes," he said. "I must be going...." IN the gathering dusk Professor Eddinger locked carefully the door of his office. He crossed beyond his desk and fumbled with his one hand for his keys. There was a cabinet to be opened, and he stared long in the dim light at the object he withdrew. He looked approvingly at the exquisite workmanship of an instrument where a generator of the cathode ray and an intricate maze of tubing surmounted electro-magnets and a round lead bulb. There were terminals for attaching heavy cables; it was a beautiful thing.... His useless arm moved to bring an imaginary hand before the window of quartz in the lead sphere. "Power," he whispered and repeated Avery's words; "power, to build a city—or destroy a civilization ... and I hold it in one hand." He replaced the apparatus in the safety of its case. "The saviors of mankind!" he said, and his tone was harsh and bitter. But a smile, whimsical, kindly, crinkled his tired eyes as he turned to his desk and its usual litter of examination papers. "It is something, Avery," he whispered to that distant man, "to belong in so distinguished a group." About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Astounding Stories. 2009. Astounding Stories of Super-Science, July 1930. Urbana, Illinois: Project Gutenberg. Retrieved May 2022 from https://www.gutenberg.org/files/29198/29198-h/29198-h.htm#pupil This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.org , located at https://www.gutenberg.org/policy/license.html .

The Power and the Glory

The Radio Amateur's Hand Book, by A. Frederick Collins is part of . You can jump to any chapter in this book here: . Chapter VI: How the Transmitting and Receiving sets work. HackerNoon’s Book Blog Post series [LINK TO TABLE OF LINK] VI. HOW THE TRANSMITTING AND RECEIVING SETS WORK The easiest way to get a clear conception of how a wireless transmitter sends out electric waves and how a wireless receptor receives them is to take each one separately and follow: (1) in the case of the transmitter, the transformation of the low voltage direct, or alternating current into high potential alternating currents; then find out how these charge the condenser, how this is discharged by the spark gap and sets up high-frequency currents in the oscillation circuits; then (2) in the case of the receptor, to follow the high frequency currents that are set up in the aerial wire and learn how they are transformed into oscillations of lower potential when they have a larger current strength, how these are converted into intermittent direct currents by the detector and which then flow into and operate the telephone receiver. How Transmitting Set No. 1 Works. The Battery and Spark Coil Circuit.--When you press down on the knob of the key the silver points of it make contact and this closes the circuit; the low voltage direct current from the battery now flows through the primary coil of the spark coil and this magnetizes the soft iron core. The instant it becomes magnetic it pulls the spring of the vibrator over to it and this breaks the circuit; when this takes place the current stops flowing through the primary coil; this causes the core to lose its magnetism when the vibrator spring flies back and again makes contact with the adjusting screw; then the cycle of operations is repeated. A condenser is connected across the contact points of the vibrator since this gives a much higher voltage at the ends of the secondary coil than where the coil is used without it; this is because: (1) the self-induction of the primary coil makes the pressure of the current rise and when the contact points close the circuit again it discharges through the primary coil, and (2) when the break takes place the current flows into the condenser instead of arcing across the contact points. Changing the Primary Spark Coil Current Into Secondary Currents.--Now every time the vibrator contact points close the primary circuit the electric current in the primary coil is changed into closed magnetic lines of force and as these cut through the secondary coil they set up in it a momentary current in one direction. Then the instant the vibrator points break apart the primary circuit is opened and the closed magnetic lines of force contract and as they do so they cut the turns of wire in the secondary coil in the opposite direction and this sets up another momentary current in the secondary coil in the other direction. The result is that the low voltage direct current of the battery is changed into alternating currents whose frequency is precisely that of the spring vibrator, but while the frequency of the currents is low their potential, or voltage, is enormously increased. What Ratio of Transformation Means.--To make a spark coil step up the low voltage direct current into high potential alternating current the primary coil is wound with a couple of layers of thick insulated copper wire and the secondary is wound with a thousand, more or less, number of turns with very fine insulated copper wire. If the primary and secondary coils were wound with the same number of turns of wire then the pressure, or voltage, of the secondary coil at its terminals would be the same as that of the current which flowed through the primary coil. Under these conditions the ratio of transformation, as it is called, would be unity. The ratio of transformation is directly proportional to the number of turns of wire on the primary and secondary coils and, since this is the case, if you wind 10 turns of wire on the primary coil and 1,000 turns of wire on the secondary coil then you will get 100 times as high a pressure, or voltage, at the terminals of the secondary as that which you caused to flow through the primary coil, but, naturally, the current strength, or amperage, will be proportionately decreased. The Secondary Spark Coil Circuit.--This includes the secondary coil and the spark gap which are connected together. When the alternating, but high potential, currents which are developed by the secondary coil, reach the balls, or electrodes, of the spark gap the latter are alternately charged positively and negatively. Now take a given instant when one electrode is charged positively and the other one is charged negatively, then when they are charged to a high enough potential the electric strain breaks down the air gap between them and the two charges rush together as described in the chapter before this one in connection with the discharge of a condenser. When the charges rush together they form a current which burns out the air in the gap and this gives rise to the spark, and as the heated gap between the two electrodes is a very good conductor the electric current surges forth and back with high frequency, perhaps a dozen times, before the air replaces that which has burned out. It is the inrushing air to fill the vacuum of the gap that makes the crackling noise which accompanies the discharge of the electric spark. In this way then electric oscillations of the order of a million, more or less, are produced and if an aerial and a ground wire are connected to the spark balls, or electrodes, the oscillations will surge up and down it and the energy of these in turn, are changed into electric waves which travel out into space. An open circuit transmitter of this kind will send out waves that are four times as long as the aerial itself, but as the waves it sends out are strongly damped the Government will not permit it to be used. The Closed Oscillation Circuit.--By using a closed oscillation circuit the transmitter can be tuned to send out waves of a given length and while the waves are not so strongly damped more current can be sent into the aerial wire system. The closed oscillation circuit consists of: (1) a spark gap, (2) a condenser and (3) an oscillation transformer. The high potential alternating current delivered by the secondary coil not only charges the spark gap electrodes which necessarily have a very small capacitance, but it charges the condenser which has a large capacitance and the value of which can be changed at will. Now when the condenser is fully charged it discharges through the spark gap and then the electric oscillations set up surge to and fro through the closed circuit. As a closed circuit is a very poor radiator of energy, that is, the electric oscillations are not freely converted into electric waves by it, they surge up to, and through the aerial wire; now as the aerial wire is a good radiator nearly all of the energy of the electric oscillations which surge through it are converted into electric waves. How Transmitting Set No. 2 Works. With Alternating Current. The operation of a transmitting set that uses an alternating current transformer, or power transformer, as it is sometimes called, is even more simple than one using a spark coil. The transformer needs no vibrator when used with alternating current. The current from a generator flows through the primary coil of the transformer and the alternations of the usual lighting current is 60 cycles per second. This current sets up an alternating magnetic field in the core of the transformer and as these magnetic lines of force expand and contract they set up alternating currents of the same frequency but of much higher voltage at the terminals of the secondary coil according to the ratio of the primary and secondary turns of wire as explained under the sub-caption of Ratio of Transformation. With Direct Current.--When a 110 volt direct current is used to energize the power transformer an electrolytic interruptor is needed to make and break the primary circuit, just as a vibrator is needed for the same purpose with a spark coil. When the electrodes are connected in series with the primary coil of a transformer and a source of direct current having a potential of 40 to 110 volts, bubbles of gas are formed on the end of the platinum, or alloy anode, which prevent the current from flowing until the bubbles break and then the current flows again, in this way the current is rapidly made and broken and the break is very sharp. Where this type of interrupter is employed the condenser that is usually shunted around the break is not necessary as the interrupter itself has a certain inherent capacitance, due to electrolytic action, and which is called its electrolytic capacitance, and this is large enough to balance the self-induction of the circuit since the greater the number of breaks per minute the smaller the capacitance required. The Rotary Spark Gap.--In this type of spark gap the two fixed electrodes are connected with the terminals of the secondary coil of the power transformer and also with the condenser and primary of the oscillation transformer. Now whenever any pair of electrodes on the rotating disk are in a line with the pair of fixed electrodes a spark will take place, hence the pitch of the note depends on the speed of the motor driving the disk. This kind of a rotary spark-gap is called non-synchronous and it is generally used where a 60 cycle alternating current is available but it will work with other higher frequencies. The Quenched Spark Gap.--If you strike a piano string a single quick blow it will continue to vibrate according to its natural period. This is very much the way in which a quenched spark gap sets up oscillations in a coupled closed and open circuit. The oscillations set up in the primary circuit by a quenched spark make only three or four sharp swings and in so doing transfer all of their energy over to the secondary circuit, where it will oscillate some fifty times or more before it is damped out, because the high frequency currents are not forced, but simply oscillate to the natural frequency of the circuit. For this reason the radiated waves approach somewhat the condition of continuous waves, and so sharper tuning is possible. The Oscillation Transformer.--In this set the condenser in the closed circuit is charged and discharged and sets up oscillations that surge through the closed circuit as in Set No. 1. In this set, however, an oscillation transformer is used and as the primary coil of it is included in the closed circuit the oscillations set up in it produce strong oscillating magnetic lines of force. The magnetic field thus produced sets up in turn electric oscillations in the secondary coil of the oscillation transformer and these surge through the aerial wire system where their energy is radiated in the form of electric waves. The great advantage of using an oscillation transformer instead of a simple inductance coil is that the capacitance of the closed circuit can be very much larger than that of the aerial wire system. This permits more energy to be stored up by the condenser and this is impressed on the aerial when it is radiated as electric waves. How Receiving Set No. I Works.--When the electric waves from a distant sending station impinge on the wire of a receiving aerial their energy is changed into electric oscillations that are of exactly the same frequency (assuming the receptor is tuned to the transmitter) but whose current strength (amperage) and potential (voltage) are very small. These electric waves surge through the closed circuit but when they reach the crystal detector the contact of the metal point on the crystal permits more current to flow through it in one direction than it will allow to pass in the other direction. For this reason a crystal detector is sometimes called a rectifier, which it really is. Thus the high frequency currents which the steel magnet cores of the telephone receiver would choke off are changed by the detector into intermittent direct currents which can flow through the magnet coils of the telephone receiver. Since the telephone receiver chokes off the oscillations, a small condenser can be shunted around it so that a complete closed oscillation circuit is formed and this gives better results. When the intermittent rectified current flows through the coils of the telephone receiver it energizes the magnet as long as it lasts, when it is de-energized; this causes the soft iron disk, or diaphragm as it is called, which sets close to the ends of the poles of the magnet, to vibrate; and this in turn gives forth sounds such as dots and dashes, speech or music, according to the nature of the electric waves that sent them out at the distant station. How Receiving Set No. 2 Works.--When the electric oscillations that are set up by the incoming electric waves on the aerial wire surge through the primary coil of the oscillation transformer they produce a magnetic field and as the lines of force of the latter cut the secondary coil, oscillations of the same frequency are set up in it. The potential (voltage) of these oscillations are, however, stepped down in the secondary coil and, hence, their current strength (amperes) is increased. The oscillations then flow through the closed circuit where they are rectified by the crystal detector and transformed into sound waves by the telephone receiver as described in connection with Set No. 1. The variable condenser shunted across the closed circuit permits finer secondary tuning to be done than is possible without it. Where you are receiving continuous waves from a wireless telephone transmitter (speech or music) you have to tune sharper than is possible with the tuning coil alone and to do this a variable condenser connected in parallel with the secondary coil is necessary. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Collins, A. Frederick. 2002. The Radio Amateur's Hand Book. Urbana, Illinois: Project Gutenberg. Retrieved April 2022, from https://www.gutenberg.org/files/6934/6934-h/6934-h.htm#chap06 This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever.  You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

How Transmitting and Receiving Sets Work

The Radio Amateur's Hand Book, by A. Frederick Collins is part of . You can jump to any chapter in this book here: . Chapter V: Electricity Simply Explained HackerNoon’s Book Blog Post series [LINK TO TABLE OF LINK] V. ELECTRICITY SIMPLY EXPLAINED It is easy to understand how electricity behaves and what it does if you get the right idea of it at the start. In the first place, if you will think of electricity as being a fluid like water its fundamental actions will be greatly simplified. Both water and electricity may be at rest or in motion. When at rest, under certain conditions, either one will develop pressure, and this pressure when released will cause them to flow through their respective conductors and thus produce a current. Electricity at Rest and in Motion.--Any wire or a conductor of any kind can be charged with electricity, but a Leyden jar, or other condenser, is generally used to hold an electric charge because it has a much larger capacitance, as its capacity is called, than a wire. As a simple analogue of a condenser, suppose you have a tank of water raised above a second tank and that these are connected together by means of a pipe with a valve in it, as shown at A in Fig. 28. Photograph unavailable--original © Underwood and Underwood. First Wireless College in the World, at Tufts College, Mass. Now if you fill the upper tank with water and the valve is turned off, no water can flow into the lower tank but there is a difference of pressure between them, and the moment you turn the valve on a current of water will flow through the pipe. In very much the same way when you have a condenser charged with electricity the latter will be under pressure, that is, a difference of potential will be set up, for one of the sheets of metal will be charged positively and the other one, which is insulated from it, will be charged negatively, as shown at B. On closing the switch the opposite charges rush together and form a current which flows to and fro between the metal plates. [Footnote: Strictly speaking it is the difference of potential that sets up the electromotive force.] The Electric Current and Its Circuit.--Just as water flowing through a pipe has quantity and pressure back of it and the pipe offers friction to it which tends to hold back the water, so, likewise, does electricity flowing in a circuit have: (1) quantity, or current strength, or just current, as it is called for short, or amperage, and (2) pressure, or potential difference, or electromotive force, or voltage, as it is variously called, and the wire, or circuit, in which the current is flowing has (3) resistance which tends to hold back the current. A definite relation exists between the current and its electromotive force and also between the current, electromotive force and the resistance of the circuit; and if you will get this relationship clearly in your mind you will have a very good insight into how direct and alternating currents act. To keep a quantity of water flowing in a loop of pipe, which we will call the circuit, pressure must be applied to it and this may be done by a rotary pump as shown at A in Fig. 29; in the same way, to keep a quantity of electricity flowing in a loop of wire, or circuit, a battery, or other means for generating electric pressure must be used, as shown at B. If you have a closed pipe connected with a piston pump, as at C, as the piston moves to and fro the water in the pipe will move first one way and then the other. So also when an alternating current generator is connected to a wire circuit, as at D, the current will flow first in one direction and then in the other, and this is what is called an alternating current. Current and the Ampere.--The amount of water flowing in a closed pipe is the same at all parts of it and this is also true of an electric current, in that there is exactly the same quantity of electricity at one point of the circuit as there is at any other. The amount of electricity, or current, flowing in a circuit in a second is measured by a unit called the ampere, [Footnote: For definition of ampere see ] and it is expressed by the symbol I. [Footnote: This is because the letter C is used for the symbol of capacitance] Just to give you an idea of the quantity of current an ampere is we will say that a dry cell when fresh gives a current of about 20 amperes. To measure the current in amperes an instrument called an ammeter is used, as shown at A in Fig. 30, and this is always connected in series with the line, as shown at B. Appendix. Electromotive Force and the Volt.--When you have a pipe filled with water or a circuit charged with electricity and you want to make them flow you must use a pump in the first case and a battery or a dynamo in the second case. It is the battery or dynamo that sets up the electric pressure as the circuit itself is always charged with electricity. The more cells you connect together in series the greater will be the electric pressure developed and the more current it will move along just as the amount of water flowing in a pipe can be increased by increasing the pressure of the pump. The unit of electromotive force is the volt, and this is the electric pressure which will force a current of 1 ampere through a resistance of 1 ohm; it is expressed by the symbol E. A fresh dry cell will deliver a current of about 1.5 volts. To measure the pressure of a current in volts an instrument called a voltmeter is used, as shown at C in Fig. 30, and this is always connected across the circuit, as shown at D. Resistance and the Ohm.--Just as a water pipe offers a certain amount of resistance to the flow of water through it, so a circuit opposes the flow of electricity in it and this is called resistance. Further, in the same way that a small pipe will not allow a large amount of water to flow through it, so, too, a thin wire limits the flow of the current in it. If you connect a resistance coil in a circuit it acts in the same way as partly closing the valve in a pipe, as shown at A and B in Fig. 31. The resistance of a circuit is measured by a unit called the ohm, and it is expressed by the symbol R. A No. 10, Brown and Sharpe gauge soft copper wire, 1,000 feet long, has a resistance of about 1 ohm. To measure the resistance of a circuit an apparatus called a resistance bridge is used. The resistance of a circuit can, however, be easily calculated, as the following shows. What Ohm's Law Is.--If, now, (1) you know what the current flowing in a circuit is in amperes, and the electromotive force, or pressure, is in volts, you can then easily find what the resistance is in ohms of the circuit in which the current is flowing by this formula: That is, if you divide the current in amperes by the electromotive force in volts the quotient will give you the resistance in ohms. Or (2) if you know what the electromotive force of the current is in volts and the resistance of the circuit is in ohms then you can find what the current flowing in the circuit is in amperes, thus: That is, by dividing the resistance of the circuit in ohms, by the electromotive force of the current you will get the amperes flowing in the circuit. Finally (3) if you know what the resistance of the circuit is in ohms and the current is in amperes then you can find what the electromotive force is in volts since: That is, if you multiply the resistance of the circuit in ohms by the current in amperes the result will give you the electromotive force in volts. From this you will see that if you know the value of any two of the constants you can find the value of the unknown constant by a simple arithmetical process. This relation between these three constants is known as Ohm's Law and as they are very important you should memorize them. What the Watt and Kilowatt Are.--Just as horsepower or H.P., is the unit of work that steam has done or can do, so the watt is the unit of work that an electric current has done or can do. To find the watts a current develops you need only to multiply the amperes by the volts. There are 746 watts to 1 horsepower, and 1,000 watts are equal to 1 kilowatt. Electromagnetic Induction.--To show that a current of electricity sets up a magnetic field around it you have only to hold a compass over a wire whose ends are connected with a battery when the needle will swing at right angles to the length of the wire. By winding an insulated wire into a coil and connecting the ends of the latter with a battery you will find, if you test it with a compass, that the coil is magnetic. This is due to the fact that the energy of an electric current flowing in the wire is partly changed into magnetic lines of force which rotate at right angles about it as shown at A in Fig. 32. The magnetic field produced by the current flowing in the coil is precisely the same as that set up by a permanent steel magnet. Conversely, when a magnetic line of force is set up a part of its energy goes to make up electric currents which whirl about in a like manner, as shown at B. Self-induction or Inductance.--When a current is made to flow in a coil of wire the magnetic lines of force produced are concentrated, as at C, just as a lens concentrates rays of light, and this forms an intense magnetic field, as it is called. Now if a bar of soft iron is brought close to one end of the coil of wire, or, better still, if it is pushed into the coil, it will be magnetized by electromagnetic induction, see D, and it will remain a magnet until the current is cut off. Mutual Induction.--When two loops of wire, or better, two coils of wire, are placed close together the electromagnetic induction between them is reactive, that is, when a current is made to flow through one of the coils closed magnetic lines of force are set up and when these cut the other loop or turns of wire of the other coil, they in turn produce electric currents in it. It is the mutual induction that takes place between two coils of wire which makes it possible to transform low voltage currents from a battery or a 110 volt source of current into high pressure currents, or high potential currents, as they are called, by means of a spark coil or a transformer, as well as to step up and step down the potential of the high frequency currents that are set up in sending and receiving oscillation transformers. Soft iron cores are not used in oscillation inductance coils and oscillation transformers for the reason that the frequency of the current is so high the iron would not have time to magnetize and demagnetize and so would not help along the mutual induction to any appreciable extent. High-Frequency Currents.--High frequency currents, or electric oscillations as they are called, are currents of electricity that surge to and fro in a circuit a million times, more or less, per second. Currents of such high frequencies will oscillate, that is, surge to and fro, in an open circuit, such as an aerial wire system, as well as in a closed circuit. Now there is only one method by which currents of high frequency, or radio-frequency, as they are termed, can be set up by spark transmitters, and this is by discharging a charged condenser through a circuit having a small resistance. To charge a condenser a spark coil or a transformer is used and the ends of the secondary coil, which delivers the high potential alternating current, are connected with the condenser. To discharge the condenser automatically a spark, or an arc, or the flow of electrons in a vacuum tube, is employed. Constants of an Oscillation Circuit.--An oscillation circuit, as pointed out before, is one in which high frequency currents surge or oscillate. Now the number of times a high frequency current will surge forth and back in a circuit depends upon three factors of the latter and these are called the constants of the circuit, namely: (1) its capacitance, (2) its inductance and (3) its resistance. What Capacitance Is.--The word capacitance means the electrostatic capacity of a condenser or a circuit. The capacitance of a condenser or a circuit is the quantity of electricity which will raise its pressure, or potential, to a given amount. The capacitance of a condenser or a circuit depends on its size and form and the voltage of the current that is charging it. The capacitance of a condenser or a circuit is directly proportional to the quantity of electricity that will keep the charge at a given potential. The farad, whose symbol isM, is the unit of capacitance and a condenser or a circuit to have a capacitance of one farad must be of such size that one coulomb, which is the unit of electrical quantity, will raise its charge to a potential of one volt. Since the farad is far too large for practical purposes a millionth of a farad, or microfarad, whose symbol is mfd., is used. What Inductance Is.--Under the sub-caption of Self-induction and Inductance in the beginning of this chapter it was shown that it was the inductance of a coil that makes a current flowing through it produce a strong magnetic field, and here, as one of the constants of an oscillation circuit, it makes a high-frequency current act as though it possessed inertia. Inertia is that property of a material body that requires time and energy to set in motion, or stop. Inductance is that property of an oscillation circuit that makes an electric current take time to start and time to stop. Because of the inductance, when a current flows through a circuit it causes the electric energy to be absorbed and changes a large part of it into magnetic lines of force. Where high frequency currents surge in a circuit the inductance of it becomes a powerful factor. The practical unit of inductance is the henry and it is represented by the symbol L. What Resistance Is.--The resistance of a circuit to high-frequency currents is different from that for low voltage direct or alternating currents, as the former do not sink into the conductor to nearly so great an extent; in fact, they stick practically to the surface of it, and hence their flow is opposed to a very much greater extent. The resistance of a circuit to high frequency currents is generally found in the spark gap, arc gap, or the space between the electrodes of a vacuum tube. The unit of resistance is, as stated, the ohm, and its symbol is R. The Effect of Capacitance, Inductance and Resistance on Electric Oscillations.--If an oscillation circuit in which high frequency currents surge has a large resistance, it will so oppose the flow of the currents that they will be damped out and reach zero gradually, as shown at A in Fig. 33. But if the resistance of the circuit is small, and in wireless circuits it is usually so small as to be negligible, the currents will oscillate, until their energy is damped out by radiation and other losses, as shown at B. As the capacitance and the inductance of the circuit, which may be made of any value, that is amount, you wish, determines the time period, that is, the length of time for a current to make one complete oscillation, it must be clear that by varying the values of the condenser and the inductance coil you can make the high frequency current oscillate as fast or as slow as you wish within certain limits. Where the electric oscillations that are set up are very fast, the waves sent out by the aerial will be short, and, conversely, where the oscillations are slow the waves emitted will be long. About HackerNoon Book Series: We bring you the most important technical, scientific, and insightful public domain books. This book is part of the public domain. Collins, A. Frederick. 2002. The Radio Amateur's Hand Book. Urbana, Illinois: Project Gutenberg. Retrieved April 2022, from https://www.gutenberg.org/files/6934/6934-h/6934-h.htm#chap05 This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever.  You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at , located at . www.gutenberg.org https://www.gutenberg.org/policy/license.html

Electricity, What a Concept!

Crypto resurfacing In the year of 2020 when Covid-19 was beginning and the world was moving into lock down, people were out of work. In every country across the world industries at mass scales were laying off workers at a never before seen rate. Families and people were left with only their savings and their hope it will end soon and maybe an alternative form of income will show itself. Then in the later half of 2020 the world experienced a crypto boom. To be specific the world experienced a massive BITCOIN boom. This is when bitcoin reached one of its highest prices ever of 26,000 USD per coin. A massive leap considering in the summer of 2010 one Bitcoin was worth 0.05 USD, according to Kai Sedgwick from news.bitcoin.com .The reason for this jump is simple. People’s revenue streams were closing at an accelerated rate, too fast for some to prepare for. People needed a new stream of revenue from a market that seemed promising, that seemed almost too good to be true. This is where Bitcoin enters. People bet their life savings, sold shares to buy it and even borrowed money from licit and illicit entities just to have a moonshot at crypto wealth. That is why so many different bitcoin and crypto platforms came out in western countries and in Asia. The boom presented a funny situation though, regardless of who made money off the boom or who lost, it was Asia, Europe, North America, South America, Australia who had the biggest stakes. All continents except Africa. Africa, too poor for crypto? YES. The answer to the question above is yes. African countries, except for a select few at this time, have no hat in the ring for crypto purely because the vast majority of African countries are impoverished. Many for different reasons others for the same reasons, does not matter. Broke is broke. No matter how you got broke you are still broke at the end of the day. Relative to the population of the continent and in comparison to the other continents, the African continent has the lowest household disposable income. This is not just common knowledge for Africans but backed by the study done by Christoph Lakner in 2013 under the title “ ” for the Centre for the Study of African Economies (CSAE). How do African incomes compare to the rest of the world? When already living in countries where it is tough to make money day to day, expendable income for luxuries is vigorously sought for and does not come easily. As such when it is attained it is carefully calculated and spent on necessities and solemnly on luxuries. A lot of western people saw crypto and by extension web3 space as a way to make expendable income to buy luxuries and even then the return on investment was initially sporadic, uncertain and given to chance. To go to a person in a third world country, in Africa, and to tell them they need to spend their rare very hard worked for extra bit of money on a currency that no one can see, that is in a virtual system, that return on investment is occasional at best and that they have a extremely rare chance at any sort of profit. That is something that is not viable for them. At all. At the time of the 2020 crypto boom in Africa you would have been scorned, ridiculed and bullied for even having the notion that it was a viable way to make money. Crypto being such an elusive concept to most poorer people, the subject would not be given the time to be learnt properly by most people. To add to that, Africans did not get involved due to seeing the fallout of people’s profits in the western world. They continuously lost large sums of money from these cryptos. The icing on the cake to this mass economic fallout was made worse by the now infamous brothers known as Ameer and Raees Cajee. The Cajee brothers both being from South Africa started the Fintech company called AfriCrypt in 2020. A bitcoin buying platform. At the time they were hailed as innovative and credited with “bringing financial freedom to Africa” by having an African founded company allowing Africans to finally buy crypto and opening the Web3 space to Africa. The celebrations soon turned sour. In April of 2021 the brothers stole all the bitcoin from their company by emptying out all of its users wallets, including that of the investors. 3.2 Billion dollars worth of bitcoin was stolen at that time. The brothers have still not been caught. The company initially gave hope to Africans but after it ended it left a cruel, bitter and unwanted taste of the crypto world in a lot of potential Africans considering using crypto or any blockchain, web3 technology. But then how long can this bitterness last? Will there be another company even better than Africrypt? Will Africans resist the future of Web3 just because of that bad experience? (left is Ameer Cajee and right is Raees Cajee) The entry of YellowCard (YellowCards Nigerian team with the YellowCard COO in the center) The bitterness people felt because of the Cajee brothers incident did not last long. There is a company better than AfriCrypt, and it is YellowCard.  YellowCard is simply a cryptocurrency buying platform. But it is currently Africa’s most prominent crypto exchange platform. It even came out earlier than AfriCrypt. YellowCard’s founding goes back to 2015. YellowCard was founded by Chris Maurice and Justin Pouriox with Chris being the company’s current CEO. Although the company is not founded by Africans this does not mean it cannot be for Africans. Most of their company is African operated and this is increasing gradually as they expand due to the increased funding they have received. After initially launching in Nigeria they are now in 13 more African countries for a total of 14 in total, this number is most likely soon to increase in the next few years as crypto aspirants throughout the continent are looking for apps like YellowCard and other Decentralised Finance apps to engage with. The countries Yellow Card is available in are almost all of the East African Community (EAC) countries except for Burundi, some of the Southern African Development Countries (SADC), A few of the Economic Community of West Africa countries (ECOWAS), A few of the Economic Community of Central African States (ECCAS) countries as well. Although only inhabiting 14 countries out of the 54 the 14 countries it inhabits almost every region of the continent. The company has recently attained a 15 million USD grant in series A funding by investors such as Block with CEO being co-founder of Twitter Jack Dorsey, Blockchain.com and CoinBase, just to name a few. All invested into this fintech company to increase YellowCards development, expansion and by extension continued normalisation of the DeFi, fintech and even web3 sphere to Africans. Since the start of Covid-19 in 2020 until now, the time of writing this, YellowCard has disclosed that their user pool has increased at least 30X times than what it previously was before 2020. They have yet to disclose the current daily or monthly user rate to the public but seeing as investors were privy to these fine details and still invested to grant them series A funding, then that is indicative that the  user rate is more than satisfactory for their rate of expansion thus more than reasonable for Jack Dorsey’s Block and other investors to invest in. In the current tech environment of Africa people are increasingly getting involved in different areas of the industry, specifically Web3, Fintech and DeFi. All in hopes to expand their expendable income or even their total income. YellowCard is a service that by design and execution is allowing and promoting this action. This is not to say everyone will profit or everyone will get rich or even that there wont be anyone who loses profit. YellowCard app is only as effective as the person using it. Even though they did not use excellent platforms like QuickNode to help build their app and scale it, like other tech startup companies have done. They have and are still well on their way to being an African tech powerhouse!

YellowCard, The Crypto Ambition of Africa

Today we will be discussing how we can set up a Flutter app and implement Google sign-in using Firebase. We'll be building a two-page app that allows users to log in using their Google Account. This is for a layer of security and to pull user's information associated with their Gmail accounts such as the user name and avatar image etc. Our final app will look like follows: Users can click on the "Sign In with Google" button, which will launch a view where users can provide their Google credentials. Upon success, control is returned to the user and Flutter navigates the user to the Welcome screen, where they can view their name, avatar, and be able to log out. Getting Started I have created my flutter application named . If you have not created any, then you can create a flutter app using the following command: social_login flutter create social_login Now we'll add the plugins required in this project. Open file and in dependencies add the plugins as: pubspec.yaml firebase_auth: ^0.16.0
google_sign_in: ^4.4.4
flutter_auth_buttons: ^0.5.0 Save the file and run: flutter pub get Build the UI Delete the code from the file and add the following code: main.dart // main.dart
import 'package:flutter/material.dart';
import 'login_page.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter Login',
      theme: ThemeData(
        primarySwatch: Colors.amber,
      ),
      home: LoginPage(),
    );
  }
} Now we'll move ahead to the login page. // login_page.dart file
import 'package:flutter/material.dart';
import 'package:flutter_auth_buttons/flutter_auth_buttons.dart';
class LoginPage extends StatefulWidget {
  @override
  LoginPageState createState() => LoginPageState();
}
class LoginPageState extends State<LoginPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.white,
        child: Center(
          child: Column(
            mainAxisSize: MainAxisSize.max,
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Image(
                image: AssetImage("assets/logo.png"),
                height: 150, 
                width: 150
              ),
              SizedBox(height: 50),
              GoogleSignInButton(
                onPressed: () {},
                darkMode: true
              ),
            ],
          ),
        ),
      ),
    );
  }
} Now we'll create a new file and name it as . Here we'll keep our code for authentication. auth.dart First, we'll import the packages required. // auth.dart
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = GoogleSignIn(); Here, we have created an instance of FirebaseAuth and GoogleSignIn. After creating an instance, we need methods as (to authenticate the user) and then (to just sign out from the current account). signIn signOut Let's create our methods in file. auth.dart // auth.dart
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = GoogleSignIn();
Future<String> signInWithGoogle() async {
  final GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
  final GoogleSignInAuthentication googleSignInAuthentication =
      await googleSignInAccount.authentication;
  final AuthCredential credential = GoogleAuthProvider.getCredential(
    accessToken: googleSignInAuthentication.accessToken,
    idToken: googleSignInAuthentication.idToken,
  );
  final AuthResult authResult = await _auth.signInWithCredential(credential);
  final FirebaseUser user = authResult.user;
  assert(!user.isAnonymous);
  assert(await user.getIdToken() != null);
  final FirebaseUser currentUser = await _auth.currentUser();
  assert(user.uid == currentUser.uid);
  return 'signInWithGoogle succeeded: $user';
}
void signOutGoogle() async{
  await googleSignIn.signOut();
} We have created our functions but now we need to call our functions in our application to let the user authenticate. So let's call our function to work for us. We'll update our login page to call after clicking the sign-in button. signInWithGoogle() // login_page.dart file
class LoginPageState extends State<LoginPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        color: Colors.white,
        child: Center(
          child: Column(
            mainAxisSize: MainAxisSize.max,
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              Image(
                image: AssetImage("assets/logo.png"),
                height: 150, 
                width: 150
              ),
              SizedBox(height: 50),
              GoogleSignInButton(
                onPressed: () {
                  signInWithGoogle().whenComplete(() {
                    Navigator.of(context).push(
                      MaterialPageRoute(
                        builder: (context) {
                        return WelcomeScreen();
                        },
                      ),
                    );
                  });
                },
                darkMode: true
              ),
            ],
          ),
        ),
      ),
    );
  }
} Here, once our sign-in is successful, we are redirecting the user to the . WelcomeScreen Build UI for WelcomeScreen To do this, run the following code: // welcome_screen.dart file
import 'package:flutter/material.dart';
class WelcomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        child: Text(
          "Welcome $name to Flutter",
           style: TextStyle(
             fontSize: 30,
             fontFamily: 'DancingScript',
             fontWeight: FontWeight.bold,
           ),
        ),
      ),
    );
  }
} Set Up a Firebase Project To create a new firebase project, go to the firebase console. Click to for creating a new project. Add Project Now, enter your project name and click continue. Follow the steps until the creation of the project. This will lead you to the Project Overview page and from here we'll be able to add firebase to our flutter app. For that, click on the Android icon and follow the steps required to create an android app. Here, you have to add the . For generating the SHA-1 key, just hover over the help (?) and click See this page. This will redirect you to the Authenticating Your Client page where you'll find commands to generate the SHA key. SHA-1 hash Then click on Register App. Next, download the google-services.json file and add it to your project-directory -> android -> app and click Next. In the third step, add the given code to the respective files. Once done, click Next and continue to console. Lastly, go to the Authentication Page -> Users tab and click on the Set up sign-in method. In Sign-in providers under the Sign-in methods tab, hover over Google provider and edit to enable Google sign-in. With this, we are done with the Google sign-in set up for our flutter app. The iOS setup is a little similar to this, but we are not going to implement it in our flutter app now. Still, you can implement it if you wish to run it on an iOS emulator or iOS mobile. To access user data such as name and email in our app, we need to update our auth file. import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = GoogleSignIn();
String name;
String email;
String imageUrl;
Future<String> signInWithGoogle() async {
  final GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
  final GoogleSignInAuthentication googleSignInAuthentication =
  await googleSignInAccount.authentication;
  final AuthCredential credential = GoogleAuthProvider.getCredential(
    accessToken: googleSignInAuthentication.accessToken,
    idToken: googleSignInAuthentication.idToken,
  );
  final AuthResult authResult = await _auth.signInWithCredential(credential);
  final FirebaseUser user = authResult.user;
  assert(user.email != null);
  assert(user.displayName != null);
  assert(user.photoUrl != null);
  name = user.displayName;
  email = user.email;
  imageUrl = user.photoUrl;
  if (name.contains(" ")) {
    name = name.substring(0, name.indexOf(" "));
  }
  assert(!user.isAnonymous);
  assert(await user.getIdToken() != null);
  final FirebaseUser currentUser = await _auth.currentUser();
  assert(user.uid == currentUser.uid);
  
  return 'Successfully loggedin: $user';
}
void signOutGoogle() async {
  await googleSignIn.signOut();
} Complete UI of WelcomeScreen Now we'll complete our UI of WelcomeScreen using the following code: // WelcomeScreen.dart file
import 'package:flutter/material.dart';
import 'auth.dart';
import 'login_page.dart';
class WelcomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Flutter Example'),
      ),
      drawer: name != null ? Drawer(
        child: ListView(
          padding: EdgeInsets.zero,
            children: <Widget>[
              DrawerHeader(
                decoration: BoxDecoration(
                  color: Colors.amberAccent,
                ),
                child: Column(
                  children: <Widget>[
                    Padding(
                      padding: EdgeInsets.zero,
                      child: CircleAvatar(
                        backgroundImage: NetworkImage(
                          imageUrl,
                        ),
                      radius: 40,
                      backgroundColor: Colors.transparent,
                    ),
                  ),
                  SizedBox(height: 10),
                  Text(
                    name,
                    style: TextStyle(
                    fontSize: 20,
                    color: Colors.black,
                    fontWeight: FontWeight.bold),
                  ),
                  SizedBox(height: 5),
                  Text(
                    email,
                    style: TextStyle(
                      fontSize: 16,
                      color: Colors.black,
                      fontWeight: FontWeight.normal
                    ),
                  ),
                ],
              ),
            ),
            ListTile(
              leading: Icon(
              Icons.exit_to_app,
              color: Colors.red,
            ),
            title: Text(
              "Sign Out",
              style: TextStyle(
                fontSize: 18,
                color: Colors.red,
              ),
            ),
            onTap: () {
              signOutGoogle();
              Navigator.of(context).pushAndRemoveUntil(
                MaterialPageRoute(builder: (context) {
                  return LoginPage();
                }), ModalRoute.withName('/'));
              }),
            ],
          ),
        ): null,
        body: Container(
          child: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              mainAxisSize: MainAxisSize.max,
              children: <Widget>[
                FlutterLogo(size: 100),
                SizedBox(height: 20),
                Text(
                  "Welcome $name to Flutter",
                  style: TextStyle(
                    fontSize: 30,
                    fontFamily: 'DancingScript',
                    fontWeight: FontWeight.bold,
                  ),
                ),
              ],
            ),
          ),
        ),
      );
    }
} Conclusion Once done, let's run our app to do authentication using Google. You can find the code on my . GitHub Repository I hope this is helpful.

Set up a Flutter app and Implement Google Sign-In Using Firebase

As the Kyrrex CEO, I would like to provide the community with the most influential scam cases in the crypto industry. How to avoid scammers, keep your assets safe on the crypto market, and some extra intel about the importance of regulation - please find the advices below. More and more investors face scam activities from fraudulent companies or hackers, losing all hard-earned funds. The Thodex case where a founder picked $2B of clients assets became a reason to take a closer look at crypto regulation. Many trading and exchanging platforms decided not to be regulated by trustworthy authorities. You can simply avoid scammers by choosing only well-regulated companies to work with. Ponzi scheme on the cryptomarket The first and the most common scheme that came to crypto is the Ponzi scheme. It came here from real markets when the company is built around the idea that dividends and profits the earliest investors should be paid from the money of the most recent investors. It works only when there are upcoming investors. There are several well-known cases in the crypto world. Thodex Thodex was a well-known Turkish exchange platform. The company had over 400,000 active clients and 390,000 of them were active. Faruk Faith Ozer has taken approximately $2B of the investors assets and flown them to Albania. As a result, six people involved in the fraudulent activities were jailed. Bitcoin Savings & Trust Bitcoin Savings & Trust (BST) was one of the earliest Ponzi schemes on the crypto market that was operated by Trendon Shavers during 2011 and 2012 years. The company offered users to invest their funds in trading and promised to obtain up to 7% weekly profits. Most of these raised funds were invested in the MtGox bitcoin exchange. During its activity, BST could attract 764,000 Bitcoins (approximately 7% of mined coins worldwide) from users around the globe. As a result, from these funds, over 150,649 Bitcoins were transferred to his personal account. The story ended with Trendon Shavers for forty years in jail. Bitconnect Bitconnect was an investment platform that was released in 2016. The main statement was that the system allows investors to lend their funds in Bitcoins through the Bitconnect platform. It requires users to lock their funds for a proper period. After it is finished, they are allowed to withdraw funds with profits in Bitconnect Coins. The profits should be obtained by a trading bot. The company wasn’t registered at all that was noted by FCA, North Carolina Secretary of State, and others that the company had no registration approval to make trading activities. Through these events where the company couldn’t prove its trading activities, Bitconnect Coin has lost 92% of its value. PlusToken PlusToken was founded in April 2018 and provided investors with stable monthly profits delivered on their crypto-wallets. The company has issued a Plus token in addition. The final scammed crypto assets have amounted from $2 to up to $2.9 billion in prices of 2019. As a result, it triggered the Bitcoin price falling. The story ended with a happy ending where the scheme creators were judged in 2020 in China. Hacking and exploits If the system wasn’t coded well, there are high chances that people lose funds. Hackers consistently review code and look for exploit opportunities to steal some money. Their activities focus on various fields such as exchangers, DeFi Rug Pulls, and wallets. BitGrail Italian exchange BitGrail was hacked in 2018, but in 2020, Italian police were suspicious that an owner could be behind several hacks that caused to be stolen approximately $147 million in cryptoassets. The person called F.F. from Florence could be behind this hack or be a person who did nothing knowing that a breach exists. This person faced charges of computer fraud, fraudulent bankruptcy, and money laundering. Coincheck The Coincheck company was hacked in January 2018, where $533 million, in 500 million NEM tokens, was stolen from hot wallets. The number of stolen tokens equals 7% of all NEM crypto assets. To prevent future losses, the company moved $110 mil in XRP tokens to the unnamed address. The reason could be that Coincheck didn’t have proper multi-signature security that must require to follow all steps to move cryptoassets. ChainSwap ChainSwap caused a vulnerability through which hackers exploited over $4 million from DeFi projects. The ChainSwap protocol offers a bridge between the Polygon, Binance Smart Chain, and Ethereum blockchains. Yesterday, the PancakeSwap platform had an issue that was a trigger for an intruder to exploit the Wilder Pancake Liquidity Pool on $ 534,000. He managed to issue 20 million WILD tokens and put them to his address on the Binance Smart Chain. Other projects have suffered similar attacks as well, Wilder World said. Africrypt The brother-owner of the South-African trading platform decided to steal $3.6 billion in 69,000 coins in April 2021. Ameer Cajee asked the community not to inform authorities because it can slow the process of inner investigation and returning funds. After information that employees had lost access to the platform seven days before the hack appeared, everything became clear. How to protect your assets? All these scam stories forced us to talk about the ways of avoiding them and keeping your assets safe more frequently. There are several simple ways to keep your crypto safe: ● You have to pay maximum attention when you use various exchange services, even if they are familiar one. They can be hacked and redirect you to a fraud site leading you step-by-step to get your funds. ● Always check, the application you may use was downloaded from a relevant publisher, and there are many positive testimonials about people’s user experiences. A company and application should have a proper level of people’s trust to be used. ● You should pay attention to emails,  messages, tweets, and so on. You have to never click on links if the messages look unfamiliar or fraudulent. Never hurry up to send your funds to someone if the message calls you to do this ASAP. ● Work only with a trustful trading platform. As an example, is going to be regulated by an EU authority. It significantly increases business processes, sets a high-security level, and provides a positive trading and investment experience. Kyrrex ● DeFi contacts are not only an opportunity to get profits from your crypto but high risks as well. You should pay extra attention and conduct some research before applying. ● A well-regulated trading platform is always better because it has a license that was hard-obtained after finishing a complicated audit process; it follows laws and rules; it passes a daily regulator’s audit; it has a better security level, etc. ● Never trust a company if it claims that it provides you with profits that are several times higher than it’s common on the market. It’s the first and most significant sign of the Ponzi scheme. ● Finally, never share security details to get access to your wallet. As we can see, it’s simple but requires much attention to . keep your crypto assets safe

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