Voltaage

voltaage

The voltage follower , as shown in Figure 1, uses virtual short and virtual break. At first glance, it seems simple and clear. If you think that there is not much content to pay attention to, then you may be wrong. Understanding the op amp's voltage-following circuit is a great help for understanding the op amp's in-phase, inverting, differential, and various op amp circuits. circuit of the op amp Figure 1 op amp voltage follower circuit Voltage follower circuit analysis If we connect the output of the op amp to its inverting input and then apply a voltage signal to the noninverting input, we will find that the output voltage of the op amp will follow the input voltage very well. Assume that the input and output voltages of the initial state op amp are both , and then when Vin increases from , will also increase in the direction of positive voltage. This is because it is assumed that Vin suddenly increases, still has no response and is still . is greater than 0, so multiply the open-loop gain of the op amp. , so that the output of the op amp begins to increase in the direction of the positive voltage. 0V 0V Vout Vout 0V Ve=Vin-Vout Vout=Ve*A Vout When increases, the output voltage is fed back to the inverting input, which then reduces the voltage difference between the two inputs of the op amp, ie, will decrease, in the same open-loop gain case. Next, will naturally decrease. Vout Ve Vout The end result is that no matter how large the input voltage is (of course, within the op amp's input voltage range), the op amp will always output a voltage that is very close to , but this output voltage is just below . There is a sufficient voltage difference between the two inputs of the guaranteed op amp to maintain the output of the op amp, which is . Vin Vout Vin Ve Vout=Ve*A Negative feedback in op amp circuits This circuit will soon reach a steady state, the amplitude of the output voltage will accurately maintain the voltage difference between the two input terminals of the op amp, which in turn will produce an accurate amplitude of the op amp output voltage. Connecting the output of the op amp to the inverting input of the op amp is called negative feedback, which is the key to self-stabilizing the system. This applies not only to op amps, but also to any common dynamic system. This stability allows the op amp to have the ability to operate in a linear mode, rather than just being saturated, fully "on" or "off", just as it is used for comparators without any negative feedback. Due to the high gain of the op amp, the voltage maintained at the inverting input of the op amp is almost equal to . For example, an op amp has an open loop gain of 200,000. If is equal to 6V, then the output voltage will be 5.999 970 000 149 999V. This produces a sufficient voltage difference at the input of the op amp, =6V-5.999 970 000 149 999V=29.999 85uV, which is amplified and then produces a voltage of 5.999 970 000 149 999V at the output, thus the system Will be stable here. Vin Vin Ve As you can see, 29.999 85uV is a small voltage, so for practical calculations, we can think that the voltage difference between the two inputs of the op amp maintained by negative feedback is . The whole process is shown in Figure 2. This is also the “virtual short” we are familiar with, and since the impedance between the two inputs of the op amp is very large, there is naturally a “virtual break”. The circuit below has a stable double-loop closed-loop gain, and the output voltage simply follows the input voltage. Ve=0V Figure 2 The role of negative feedback One big advantage of using negative feedback is that we don't have to worry about the actual voltage gain of the op amp, as long as it is large enough. If the op amp's voltage gain is not 200 0000 but 250 000, this will cause the op amp's output voltage to be closer to , and the voltage difference between the smaller inputs will be used to produce the desired output voltage. In the circuit illustrated in Figure 2, the output voltage is also equal to the input voltage at the inverting input of the op amp. Therefore, for the circuit design engineer, in order to achieve a stable closed-loop gain of the amplifier circuit, the open-loop gain of the op amp does not have to be an accurate value, and the negative feedback causes the system to self-adjust. Vin Using negative feedback improves linearity, gain stability, output impedance, and gain accuracy, but using negative feedback also poses a serious problem, which is to reduce system stability for voltage-following circuits with unity gain. This is the worst case scenario, especially when driving capacitive loads, interested students can check the relevant information themselves. Regarding the op amp circuit, many times we are infused with the inverting end to follow the in-phase end. As mentioned above, can't we follow the inverting end of the phase? For the voltage follower circuit mentioned today, only the inverting terminal follows the non-inverting terminal. Here, if a positive input voltage is applied to the inverting terminal and the output is connected to the non-inverting terminal, and the output is assumed to be 0. will be a negative voltage, multiplied by the open-loop gain of the op amp, and the output will be a A negative voltage, returning to the non-inverting input of the op amp, will further result in a larger negative absolute voltage difference. Soon the output of the op amp will be saturated, and naturally the in-phase will not follow the inverting end. Ve However, for an op amp, if a reference voltage is applied to the inverting terminal, and other electronic components, such as a triode, MOS, etc., the overall loop of the op amp forms a negative feedback, and the in-phase end can also follow the inverting end. And this naturally breaks the rule that the inverting end of the familiar op amp follows the in-phase end. The voltage of the op amp follows the circuit, "virtual short", "virtual break" is the surface, and negative feedback is the root. Based on this root, it can help us understand the ever-changing op amp circuit.

The Voltage Follower Circuit of The Operational Amplifier

Since the reverse withstand voltage of the is limited, when used in a high- voltage environment, it is often necessary to use plurality of step-recovery rectifier diodes in series to meet the need of reverse withstand voltage. Due to the inconsistency in the volt-ampere characteristics, turn-on time, and recovery charges of the diode during the production process, the voltage sharing problem occurs when used in series, which causes the reverse voltage of a certain diode to be too high and damaged, disturbing the normal operation of other diodes, which ultimately affects the reliability and stability of the entire device. step-recovery diode 1. Characteristics and Factors of Uneven Voltage of the Diode 1.1 Characteristics Diodes are very commonly-used power electronic devices. Generally, we are easier to miss the key parameters of familiar devices, and only care about macroscopic parameters on the macro level, such as reverse withstand voltage, on-state current, and reverse leakage current. While the junction capacitance, turn-off and turn-on characteristics of the diode are easily overlooked. 1.2 Uneven Voltage Problem The main reason for the voltage sharing problem may be caused by either internal reasons or external ones. The internal reasons is related to the processing technology, and the external cause is about the external circuit. The volt-ampere characteristics of the diodes produced in the same batch are inconsistent, resulting in static uneven voltage of the diode; the inconsistency between the reverse recovery time and the on state state causes the dynamic uneven voltage of the diode. External circuit design can cause stray inductance and capacitance, which can cause uneven voltage problems in high-voltage high-frequency environments. 2. Analysis of the Uneven Voltage Problem 2.1 Analysis in Macroscopic Scale At the macro level, the diodes in series does not need to have voltage sharing, the main consideration is the influence of the diode itself. As shown in Figure 1, the two diodes are connected in series with an external reverse DC voltage. The diode with a small reverse saturation current can withstand a large voltage as the two diodes are connected in series, and the reverse saturation current is constant under an externally applied voltage rating. As shown in Figure 2, assumed that there is difference in the reverse saturation current between the two diodes, and the reverse saturation current of D2 is smaller, the above conclusion can be clearly drawn. FIG 1. Circuit of Two Diodes Connected in Series In actual operation, macroscopically, diodes have different voltage drops due to their own differences as shown in Figure 2. When the the voltage drop on D2 from the external voltage U increases reaches the critical point, the voltage drop of D1 is relatively small and still in the safe and stable region due to its large reverse saturation currents. FIG 2. Volt-ampere characteristics Diagram of Diode According to the above analysis, when U increases continuously. , the voltage drop on D2 will break through the critical transition voltage, causing the current to increase sharply. As D1 and D2 are connected in series in the main circuit, the current of D1 certainly increase with D2. However, the volt-ampere curve of D1 shows that the reverse voltage drop of D1 should reach the breakover voltage when a large current pass through it, so the sum of u1 and u2 is greater than U, which proves the speculation above is not true. Therefore, when U increases, the voltage of D2 will not continue to increase, and the voltage of D1 will keep increasing until its value is more than the sum of the reverse withstand voltages of the two tubes, at which point diode breakdown occurs. 2.2 Analysis in Microscopic Scale The pins and the layout of the diode on the board naturally evolve into and inductance in a high-voltage and high-frequency environment. The introduction of stray capacitance and inductance directly affects the turn-on and turn-off waveforms of the diode. stray capacitance The introduction of capacitance prevents a sudden change in voltage and the introduction of an  inductance prevents a sudden change in current. Figure 3 is the equivalent circuit diagram of the diodes in series at high frequency. In the figure, C1 is the junction capacitance, R is the reverse resistance, C2 is the stray capacitance at the high voltage, C3 is the stray capacitance formed by the diode to the ground. FIG 3. equivalent Circuit Diagram of series diodes at high frequency 3. Applications of Diodes in Series The high-frequency power supply of the electrostatic precipitator outputs high-frequency PWM waves, and the waves pass through the boosting transformer and the rectifier module to finally become an approximate linear voltage waveform. The rectifier module is integrated in the boosting transformer, and the diodes are in series. Because the voltage level is relatively high, it is generally considered to reach 10KV or more. Since the requirement for the accuracy of the output voltage waveform is not high, the diode can be directly connected in series, and the high-frequency rectifier diode is selected. The rectified output simulation waveform is shown in FIG. 4, and the measured waveform is shown in FIG. 5. FIG 4. Simulation Waveform FIG 5.  Measured Waveform As shown in the figures, the rectified output voltage has high and low peaks due to the influence of stray parameters. With the continuous development of science and technology, the manufacturing process of diodes is constantly improving, and the influence of its own factors is negligible. 4. Conclusion By simply analyzing the voltage sharing problem of the from both macroscopic and microscopic perspectives, it is concluded that when the diode is used in series in a high-voltage high-frequency environment, the diode itself will generate uneven voltage but not cause breakdown. series diode The uneven voltage generated by external factors is the result of breakdown of the diode, and it will cause even more serious problems.

Misunderstanding of Voltage Sharing Problem of Series Diode 

Classification of Computing in Memory Principles - Digital Computing in Memory Vs. Analog Computing

Nobel Prize Winner Geoffrey Hinton Explores Two Paths to Intelligence in AI Lecture

Driving Innovation: Patents and Projects Shaping the Automotive Industry

ড্রাইভিং ইনোভেশন: পেটেন্ট এবং প্রকল্পগুলি মোটরগাড়ি শিল্পকে আকার দেয়

Impulsando la innovación: patentes y proyectos que configuran la industria automotriz

Poticanje inovacija: patenti i projekti koji oblikuju automobilsku industriju

イノベーションの推進: 自動車産業を形成する特許とプロジェクト

ນະວັດຕະກໍາການຂັບລົດ: ສິດທິບັດ ແລະໂຄງການສ້າງອຸດສາຫະກໍາລົດຍົນ

Go Kganna Boitlhamelo: Dipatente le Diprotšeke tše di Bopago Intasteri ya Dikoloi

Продвижение инноваций: патенты и проекты, формирующие автомобильную промышленность

Kutyaira Innovation: Patents uye Mapurojekiti Kugadzira Iyo Indasitiri Yemotokari

ขับเคลื่อนการสร้างสรรค์นวัตกรรม: สิทธิบัตรและโครงการที่กำหนดรูปลักษณ์ของอุตสาหกรรมยานยนต์

Pagmamaneho ng Innovation: Mga Patent at Proyekto na Humuhubog sa Industriya ng Automotive

Innovatsiyalarni qo'zg'atuvchi: avtomobil sanoatini shakllantiruvchi patentlar va loyihalar

I-Driving Innovation: Amalungelo Obunikazi Nemiklamo Ebumba Imboni Yezimoto

Data Migration from Dell ECS to MinIO

نقل البيانات من Dell ECS إلى MinIO

Migración de datos de Dell ECS a MinIO

Dell ECS から MinIO へのデータ移行

ការផ្ទេរទិន្នន័យពី Dell ECS ទៅ MinIO

Migration ya ba données depuis Dell ECS na MinIO

ການຍ້າຍຂໍ້ມູນຈາກ Dell ECS ໄປຫາ MinIO

Миграција на податоци од Dell ECS во MinIO

Migrasi Data daripada Dell ECS kepada MiniIO

Dell ECS kaqmanta MinIO kaqman Willayta Migracion

Migrácia dát z Dell ECS na MinIO

ዳታ ማይግሬሽን ካብ Dell ECS ናብ MinIO

Dell ECS-dan MiniIO-ga ma'lumotlarni ko'chirish

Bitcoinized Fossil Fuel

Биткоинизированное выкапнёвае паліва

Combustible fósil bitcoinizado

Combustible fossile bitcoinisé

דלק מאובן שעבר ביטקוין

ビットコイン化された化石燃料

Bahan Api Fosil Bitcoin

Ibicanwa bya Bitcoin

பிட்காயின் செய்யப்பட்ட புதைபடிவ எரிபொருள்

Сӯзишвории истихроҷи биткоинизатсияшуда

เชื้อเพลิงฟอสซิล Bitcoin

I-Bitcoinized Fossil Fuel

The IISc Memristor: The Dawn of a New Era in Computing and AI Accelerators

Authors:
(1) Taha Laroussi, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France;
(2) Mojtaba Jarrahi, Universit´e Paris-Saclay, CNRS, FAST, 91405 Orsay, France;
(3) Gabriel Amselem, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France. Table of Links Abstract and Introduction Methods Results Model Discussion, Acknowledgements and References Supplementary Material II. METHODS A. Culture preparation C. reinhardtii strain CC-125 (Chlamydomonas Resource Center, University of Minnesota, MN, USA) were cultured on a solid medium prepared with TrisAcetate-Phosphate (Gibco™ TAP, ThermoFischer Scientific, France) and agar every 4 weeks, to keep the strain motile, responsive to light and prevent as much as possible the cells from sticking to the walls of the devices. For experiments, colonies of C. reinhardtii were picked from solid cultures and recultured in liquid TAP. The cultures were placed in an agitating incubator at 176 rpm, under a day/light cycle of 14h/10h with an illuminance of 60 µmol · m−2 · s −1 and at a fixed temperature of 22◦C. The cells reached maximum motile cell density within 3 days [16], after which a solution of swimming C. reinhardtii was obtained. Before being used for experiments, the cultures underwent a series of centrifugation steps. This enabled to concentrate the algal solution, get rid of low-motility and dead algae, and of cellular debris. First, 45 mL of the liquid culture were centrifuged at 1057g for 10 minutes. Then, 39 mL of the supernatant was removed, and the bottom 6 mL were centrifuged at 73g for 2 minutes. The supernatant, containing the motile cells, was kept and centrifuged again at 285g for 5 minutes. The amount of supernatant was adjusted to obtain the desired algae final concentration. B. Experimental setup An array of shallow cylindrical wells was made in polydimethylsiloxane (PDMS, Dow-Corning Sylgard 184), using standard soft lithography techniques [17]. The wells had a depth of 32 µm and diameters ranging from 200 µm to 500 µm. The PDMS was rendered hydrophilic by plasma cleaning. Then, a drop of ≈ 10 µL of the algal solution was deposited on the PDMS. The device was closed with a plasma-activated glass slide by applying gentle pressure. The trapped algae were observed under a Nikon TI microscope, using a 4x objective. Images were recorded at 10 fps with a CMOS camera (Hamamatsu ORCAFlash4.0 LT, Hamamatsu Photonics, France). A longpass red filter with a 645 nm cut-on wavelength (Newport RG645) was placed between the microscope’s light source and the microwells. A 3 mm blue LED with a wavelength λ = 470 nm and a light intensity of 7000 mcd (Plan`ete Leds, France) was placed on the microscope’s plate, approximately 2 cm away from the microfluidic chip, on the same plane. The LED operating voltage range was between 2.4 V and 3.2 V and its operating current was 20 mA. The light intensity was tuned by varying the applied voltage. An illustration of the setup is shown in Fig. 1. The algae concentration ϕ was determined in each well from images captured at the beginning of the experiments, before exposition to a light stimulus. Initially, the algae swam randomly and were distributed homogeneously in each well. They were identified by thresholding the images, and the total area they occupied in each well was determined. The concentration in algae was then defined as the fraction of surface area occupied by the algae in the well. C. Measuring the local light intensity We estimated the local light intensity inside a well using the number of photons reaching the sensor of the camera. First, we determined the camera offset value by blocking off all the light to the camera and taking a 16-bit image. The spatial average intensity in grey value of all the pixels in the image was the camera’s offset. Then, a 16-bit setup image of the sample was taken at the current experimental condition, with the light of the microscope turned off and the blue LED light on. The camera offset value was then subtracted from each pixel in the setup image. The grey values were first converted to number of electrons by dividing each pixel in the image by the conversion gain of the camera. The electrons were converted to photons by dividing the number of electrons from each pixel by the quantum efficiency (QE) of the sensor at λ = 470 nm. Last, the local light intensity inside a well was computed as the average number of photons within the well. This paper is available on arxiv under CC 4.0 license. Authors: (1) Taha Laroussi, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France; (2) Mojtaba Jarrahi, Universit´e Paris-Saclay, CNRS, FAST, 91405 Orsay, France; (3) Gabriel Amselem, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France. Authors: Authors: (1) Taha Laroussi, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France; (2) Mojtaba Jarrahi, Universit´e Paris-Saclay, CNRS, FAST, 91405 Orsay, France; (3) Gabriel Amselem, Laboratoire d’Hydrodynamique (LadHyX), CNRS, Ecole Polytechnique, Institut Polytechnique de Paris, 91120 Palaiseau, France. Table of Links Abstract and Introduction Abstract and Introduction Methods Methods Results Results Model Model Discussion, Acknowledgements and References Discussion, Acknowledgements and References Supplementary Material Supplementary Material II. METHODS A. Culture preparation C. reinhardtii strain CC-125 (Chlamydomonas Resource Center, University of Minnesota, MN, USA) were cultured on a solid medium prepared with TrisAcetate-Phosphate (Gibco™ TAP, ThermoFischer Scientific, France) and agar every 4 weeks, to keep the strain motile, responsive to light and prevent as much as possible the cells from sticking to the walls of the devices. For experiments, colonies of C. reinhardtii were picked from solid cultures and recultured in liquid TAP. The cultures were placed in an agitating incubator at 176 rpm, under a day/light cycle of 14h/10h with an illuminance of 60 µmol · m−2 · s −1 and at a fixed temperature of 22◦C. The cells reached maximum motile cell density within 3 days [16], after which a solution of swimming C. reinhardtii was obtained. Before being used for experiments, the cultures underwent a series of centrifugation steps. This enabled to concentrate the algal solution, get rid of low-motility and dead algae, and of cellular debris. First, 45 mL of the liquid culture were centrifuged at 1057g for 10 minutes. Then, 39 mL of the supernatant was removed, and the bottom 6 mL were centrifuged at 73g for 2 minutes. The supernatant, containing the motile cells, was kept and centrifuged again at 285g for 5 minutes. The amount of supernatant was adjusted to obtain the desired algae final concentration. B. Experimental setup An array of shallow cylindrical wells was made in polydimethylsiloxane (PDMS, Dow-Corning Sylgard 184), using standard soft lithography techniques [17]. The wells had a depth of 32 µm and diameters ranging from 200 µm to 500 µm. The PDMS was rendered hydrophilic by plasma cleaning. Then, a drop of ≈ 10 µL of the algal solution was deposited on the PDMS. The device was closed with a plasma-activated glass slide by applying gentle pressure. The trapped algae were observed under a Nikon TI microscope, using a 4x objective. Images were recorded at 10 fps with a CMOS camera (Hamamatsu ORCAFlash4.0 LT, Hamamatsu Photonics, France). A longpass red filter with a 645 nm cut-on wavelength (Newport RG645) was placed between the microscope’s light source and the microwells. A 3 mm blue LED with a wavelength λ = 470 nm and a light intensity of 7000 mcd (Plan`ete Leds, France) was placed on the microscope’s plate, approximately 2 cm away from the microfluidic chip, on the same plane. The LED operating voltage range was between 2.4 V and 3.2 V and its operating current was 20 mA. The light intensity was tuned by varying the applied voltage. An illustration of the setup is shown in Fig. 1. The algae concentration ϕ was determined in each well from images captured at the beginning of the experiments, before exposition to a light stimulus. Initially, the algae swam randomly and were distributed homogeneously in each well. They were identified by thresholding the images, and the total area they occupied in each well was determined. The concentration in algae was then defined as the fraction of surface area occupied by the algae in the well. C. Measuring the local light intensity We estimated the local light intensity inside a well using the number of photons reaching the sensor of the camera. First, we determined the camera offset value by blocking off all the light to the camera and taking a 16-bit image. The spatial average intensity in grey value of all the pixels in the image was the camera’s offset. Then, a 16-bit setup image of the sample was taken at the current experimental condition, with the light of the microscope turned off and the blue LED light on. The camera offset value was then subtracted from each pixel in the setup image. The grey values were first converted to number of electrons by dividing each pixel in the image by the conversion gain of the camera. The electrons were converted to photons by dividing the number of electrons from each pixel by the quantum efficiency (QE) of the sensor at λ = 470 nm. Last, the local light intensity inside a well was computed as the average number of photons within the well. This paper is available on arxiv under CC 4.0 license. This paper is available on arxiv under CC 4.0 license. available on arxiv

Short-term Memory Effects in the Phototactic Behavior of Microalgae: Methods

ChatGPT in Test Design: How to Streamline QA Processes

Stories, News & Mentions about VOLTAAGE

Voltaage’s Stories on HackerNoon