How to Build a Circuit: Breadboards for Beginners

What is Breadboard?

When learning how to build a circuit, the breadboard is one of the most basic components. There are many small jacks on the breadboard, which are specially designed and manufactured for solderless experiments of electronic circuits. A breadboard consists of a plastic block holding a matrix of electrical sockets of a size suitable for gripping thin connecting wire, component wires, or the pins of transistors and integrated circuits (ICs). The sockets are connected inside the board, usually in rows of five sockets. Since various electronic components can be inserted or pulled out at will according to needs, welding is eliminated, circuit assembly time is saved, and components can be reused, so it is very suitable for the assembly, debugging, and training of electronic circuits.

How to Use Breadboards

You can use a breadboard to make quick electrical connections between components- like resistors, LEDs, capacitors, etc so that you can test your circuit before permanently soldering it together. Without welding and manual wiring, the circuit and components can be tested by inserting the component into the hole, which is convenient to use. Before use, determine which component's pins should be connected together, and then insert them into the same group of 5 small holes.

Example: LED Lighting

Materials: One breadboard, several connecting wires (the connecting wires should use needle-shaped wires at both ends), one led light, and one 3V button battery.

1. First, put the battery into the battery holder (this can be bought online), and plug it into the breadboard. Then, insert the battery holder into the left and right parts of the breadboard. Parts are separated by grooves to avoid a short circuit between the positive and negative poles of the power supply).

1. Lead two wires from the positive and negative poles of the battery, and then plug the LED into any two grids that are not conductive on the breadboard (the long pin of the led is positive and the short pin is negative), and finally connect the wires from the positive and negative poles of the battery to the two LED segments.

Basic Principles of Breadboard Wiring

Complete the circuit overlap on the breadboard, different people have different styles. However, no matter what style or habit, the following basic principles must be paid attention to when completing the circuit overlap:

1. The fewer connection points, the better

Each additional connection point actually increases the probability of failure artificially. There are common faults such as impassability in the breadboard hole, loose wire, and broken wire inside.

2. Try to avoid overpasses

The so-called "overpass" means that components or wires ride on other components or wires. Beginner is easy to make such mistakes. It will bring trouble to the replacement of components in the later stage. On the other hand, in the event of a failure, the messy wires can easily make people lose confidence.

3. Try to be as reliable as possible

There are two phenomena that need attention:

• Breadboard integrated circuits are easy to loosen. Therefore, for integrated circuits such as operational amplifiers, it is necessary to press down forcefully. Once it is not reliable, the position needs to be changed.
• The pins of some components on the breadboard are too thin, so please be careful to move them slightly. If you find that they are not secure, you need to change the position.

Breadboard Using Tips for Beginners

1. When installing discrete components, it should be easy to see their polarity and signs. After placing the component pins, bend them where needed. In order to prevent the exposed leads from short-circuiting, a wire with a sleeve must be used, and the component pins are generally not cut to facilitate repeated use. Generally, do not insert components with a pin diameter> 0.8mm, so as not to damage the elasticity of the contact piece inside the socket.
2. The pins of integrated circuits that have been used many times must be repaired neatly, the pins cannot be bent, and all the pins should be slightly skewed outward so that the lead angles and the jacks can be reliably contacted. The arrangement of the components on the breadboard should be determined according to the circuit diagram in order to facilitate the wiring. In order to be able to correctly route and facilitate wire checking, the insertion direction of all ICs must be kept the same, and which cannot be inserted upside down for the convenience of temporary wiring or to shorten the length of the wire.
3. According to the sequence of the signal flow, the method of installation and debugging is adopted. After the components are installed, first connect the power cord and the ground wire. In order to check the line conveniently, try to use different colors for the line. For example, the positive power supply generally uses a red wire, the negative power supply uses the blue, the ground wire uses the black, and the signal wire uses the yellow. Other colors can also be selected according to the real conditions.
4. The breadboard should use a single-strand wire with a diameter of about 0.6mm. Cut the wire according to the distance of the wire and the length of the jack. The wire end is required to be cut into a 45º, and the stripped length of the wire end is about 6mm. All the wires are required to be inserted into the bottom plate to ensure good contact. In addition, bare wires should not be exposed to prevent disconnection with other wires.
5. The connection is required to be tightly attached to the breadboard to avoid collision and ejection of the breadboard, resulting in poor contact. The wiring must pass around the integrated circuit, and it is not allowed to cross the integrated circuit, and the wires must not be overlapped with each other, try to be horizontal and vertical. This is conducive to line wiring and checking, and components replacement.
6. It is best to connect a capacitor with a capacity of tens of microfarads in parallel between the input terminal of each power supply and the ground, so as to reduce the impact of current during transients. In order to suppress the high-frequency components in the power supply, a high-frequency decoupling capacitor should be connected in parallel at both ends of the capacitor, generally 0.01~0.047Uf.
7. During the wiring process, it is required to place the various components in the corresponding position on the breadboard and mark the pin numbers used on the circuit diagram to ensure the smooth progress of debugging and troubleshooting.
8. All ground wires must be connected together to form a common reference point.

Maintenance of the Breadboards

Using a breadboard is more convenient than using a soldering method, easy to replace wires and components, and can be used multiple times. However, the breadboard should be maintained during daily use.

After multiple uses of the breadboard, the spring sheet will become loose and the elasticity will become poor, which is easy to cause poor contact and virtual welding. They are difficult to find out. The breadboard that has been used many times should be uncovered from the back; the spring sheet with poor elasticity should be taken out, repaired, and then inserted into the original position. This can enhance the elasticity and increase the reliability and service life of the breadboard.

In addition, pay attention to where the breadboard is used. Large-volume, high-quality, or high-power components cannot be plugged into the breadboard because the breadboard jacks are small and the leads of such large components are relatively thick. At this time, the components can only be placed outside the board. Use a single strand of hard wire to solder to the lead, and then insert it into the breadboard.

Breadboards are not suitable for high-frequency circuits because the lead inductance and distributed capacitance of the breadboard are relatively large, which has a great impact on the performance of high-frequency circuits.

A breadboard is suitable for integrated circuits, especially for digital integrated circuits because digital integrated circuits usually have low operating frequency and low power, and they use fewer RC components. It is more difficult for discrete component circuits to use breadboards, especially for circuits with high frequency and high power.

Reference Note:

https://www.apogeeweb.net/electron/the-best-tech-guide-to-electronic-breadboards.html