# Questions tagged [power-electronics]

Refers to the conversion of electric power by using solid state components such as semiconductors. Can also generally apply to the field of electrical engineering which works with power electronics.

1,240 questions
592 views

### finding Q point of thyristor drive circuit.

how to find Q point of the transistor shown in the image. the problem is specifically due to pulse transformer.
85 views

### Superposition Theorem Question

Calculate I' in figure 8-14(a) I need help on finding I' RT= 1/4+1/4+1/2 = 1 RT= 4+2+1=7 Then i applied ohm's law to find the current IT=14/7=2mA Am i calculating anything wrong?
7k views

### What is the difference between peak-power, average power and true RMS power in RF measurement?

What difference between peak-power, average power and true RMS power in RF measurement? I have read a peak-power measurement can calculate average power measurement also. Does any of these needs ...
2k views

### Current controller circuit to drive solenoid bank

I am working on building a current controller circuit used to drive 8 solenoids (for those interested, the solenoids produce magnetic fields for use in a Zeeman Slower). My problem is that there is ...
3k views

### Electronic flasher with low load detection

The circuit above is an existing flasher without low load detection. I am trying to develop electronic 2-wheeler flasher with low load detection. While Googling, I got a circuit with relay in it, one ...
273 views

### How do I reverse this following circuit, i.e. when the laser is off then it should stop buzzing?

All the necessary symbols are given in the circuit itself. When the laser is shooted to photoresistor, then buzzer stops. I want to stop the buzzer as soon as laser gets off.
74k views

### Why does the USA use 110V and UK use 230-240V?

Why does the USA use 110V and UK use 230-240V? What are the advantages? Explain me with calculation. Why do they use different frequencies like 50Hz, 60Hz? What is the reason?
797 views

### Galvanic Isolation with Voltage Equalization?

I need to equalize the ground voltage between the input and output of an isolated DC-DC power supply while still maintaining galvanic isolation. Is there a way to do this? The reason I need this is ...
585 views

### What does sequences like 1-3, 1-10, 1-3-10 etc in a spectrum analyzer mean?

I have read in a paper explaining spectrum analyzer basic 'When selecting the RBW(resolution BW), there is usually a 1-10 or a 1-3-10 sequence of RBWs available. More RBWs are better because this ...
192 views

### Rigging an MRI machine with club speakers and lights

I'm using a magnetic resonance imaging (MRI) machine to fMRI trial subjects while they experience club-like conditions. This means I need loud, high-fidelity speakers, flashing multicolored lights ...
168 views

### How to add a desirable phase shift in the input from 3-phase ac mains?

I want to build a 12 pulse rectifier circuit. I know delta-wye or wye-delta transformers can be used to add phase shifts equal to the multiples of 30, but I don't want to use transformers. Is there ...
153 views

### Multiple voltage output power supply

I want to power a Raspberry Pi and a set of speakers from one power supply. I thought about uncasing the existing power supplies and connecting them to a power connector but that seemed a bit ...
340 views

### How can I prototype an Aluminum-clad board?

I have a fairly thermal-heavy design that I want to prototype on something resembling an aluminum-clad (or -core) board. Alas, it's not FR-4 and the low-volume run costs are exorbitant. What is a ...
3k views

### Equivalent width of CMOS gate?

When setting up the gate that is defined as OUTPUT=(AB+C)' Why is the pull up network equivalent width equal to 4? I know the pull down network is counted in series, so you just add the resistor in ...
3k views

### Difference between rising edge falling edge D flip flop (asynchronous reset)?

I am answering a question about a D Flip-Flop with Asynchronous Reset with the reset output '0', that is set to be rising edge triggered. What i don't know is the difference between a rising edge ...
123 views

### Is the circuit right?

simulate this circuit – Schematic created using CircuitLab I have found this questions and the circuit seems worong to me because the output terminal hasn't end point. If we add a more ...
1k views

### Which capacitor for a high current resonant system?

I would like to build a induction heater. simulate this circuit – Schematic created using CircuitLab V1 will be a ZVS system that is out of scope of the question. Accordint to my computations ...
14k views

### Average output voltage of a fully controlled full wave rectifier

What is the average voltage for a fully controlled bridge rectifier with firing angle $\alpha$ ? In a lot of web resources it is said to be: $$\frac{V_{max}}{\pi} (1+ cos(\alpha))$$ For example ...
34k views

### What is Overmodulation?

The Wikipedia article is very short and doesn't explain the concept very well, and there aren't any other sites that I can find that give a simple explanation. What does it mean by 100% modulation? I ...
6k views

### How do I drive a MOSFET working under high voltage while keeping it insulated from the rest of the circuit?

I want to drive a MOSFET with a 50Hz, 50% duty cycle clock pulse. The voltage to be switched is as high as 300V DC. The section inside the dashed lines will stay electrically isolated from the rest of ...
401 views

### Is it possible that LED power supply is interfering with my webcams USB connection?

Not sure it is a right place to ask this question but I'm pretty out of options. I'm building DIY home-studio LED lights out of multiple 12V LED bulbs. I'm using a dedicated power supply connected to ...
709 views

### Circuit working in breadboard but not perfboard

I am making a circuit to unlock my car doors. The central locking in my car works with 2 wires one at 12V, the other at 0V. When the 12V line is pulled low, the door locks. When the 0V line is pulled ...
411 views

### Is the a limit for screen resolution? [closed]

I think I am right in saying that 8k UHD is the highest a screen can go, so is there a limit to the number of pixels on a screen, limit to what the eye can recognise or what is physically possible? ...
171 views

### Unstable 96V DC to 3.3V Supply

So I've got a huge battery at 96VDC with a couple of electric motors hooked up to it that can draw huge amounts of current -- up to 600 amps. I need to power a few small electronics for a data ...
16k views

### What to plug in first to usb charger when charging: wall outlet or cell phone and why? [closed]

I asked this question on Physics StackExchange but was advised to ask it here. When I charge me cell phone or notebook or whatever device what should I plug in first? Should I at first plug in usb ...
3k views

### Power Resistor TO-263 in Layout (Eagle) [duplicate]

I am using this Power Resistor here and I am trying to put it in my layout. The Problem is I can't find any .lib (TO-263 or D2PK) file in Eagle or at least a similar package. Any Help?
1k views

### How to connect a microphone to apply audio signal to electronic circuit?

I am working on a project where we have to design a band pass filter signals in audio frequency range. We have tested the filter design using Signal generator already, and now we want to see if it ...
143 views

### Why do we use (0,+V) in digital electronics (eg processors) instead of (-V/2,+V/2)? [closed]

Would making the default voltages for 0 and 1 where relevant +|- V/2 save 1/2 power?
201 views

### How to take samples of 300V signal [duplicate]

I want to digitize (convert from analog to digital) a signal that can vary from -300 volts to +300 volts. Can anybody suggest how to handle this high voltage signal?
3k views

### Problem with PWM generator SG1525(SG3525)

I am designing a Full Bridge DC to DC convertor using SG1525(SG3525). I'm doing the simulations in OrCAD Capture(PSpice). Actually, I've successfully simulated the Power section of the converter using ...
249 views

### How is voltage gain typically achieved?

Excluding opamps and other IC's, how would one go about replicating a low voltage wave into a high voltage one?
205 views

### Why does a battery starts working on rubbing?

Whenever my TV remote or wireless keyboard/mouse stops working,I take the batteries out and rub the two terminals with some rough cloth and it works fine.I've observed that this works a lot of times(...
2k views

### Why my full-wave bridge type diode rectifier circuit begins an analysis from 8. second on Matlab Simulink?

Hi, I am working on Matlab Simulink's work page to get full-wave and half-wave bridge-type-diode rectifiers as could be seen in the picture. But, according to my Scope2 screen when I double clicked ...
4k views

### Determine the line phase and line to line voltage

Three single-phase transformer are connected as a transformer bank rated at 18MVA, 13.8kV(delta)/120kV(Y) // one side of the transformer bank is connected to a 120 kV transmission line and ...
7k views

### What does the line to line voltage mean? [closed]

What does the line to line voltage mean? For WYE connection is Vna line to line or Van? How about Delta connection?
229 views

### How to design a Circuit that can turn a LED ON depending on the input voltage

I have three LEDs, and I want to turn the first LED ON if the input voltage is 4V , I want to turn the first and second LED ON if the input voltage is 8V and so on. Is it possible to do without any ...
5k views

### Simulating a Flyback converter using Matlab / Simpowersystems, cannot get it to work, any tips?

I have created a flyback converter model using Simpowersystems in Simulink/Matlab. But it always gives me the wrong answer! I have simulated the same system using PLECS and Simscape/simulink and got ...
466 views

### Doubt in PMDC motor pulsed switching current

I am controlling a dc motor by switching through the MOSFET. I am able to run the DC MOTOR and I have measured the current through scope by putting a RESISTOR SERIES of the DC MOTOR. My doubt is, ...
1k views

### How to calculate switching frequecncy [duplicate]

I am trying to control a brushed DC motor with PWM control through a MOSFET, below is the basic circuit for an idea. The PWM signal is given from a microcontroller to the gate driver IC which drives ...
2k views

Why we doing the full load and no load test for induction motor What is the purpose ? and can you provide some example? Why we doing the full load test and find power and stuff and also for no ...
1k views

### How to limit current of an AC signal

For my project, I'm trying to work with the principle of electrovibration. This principle is about simulating textures using low current electricity on an insulated conductive surface (see Wikipedia). ...
679 views

### Buck Converter with resistive load

I was reading a chapter on Step down Choppers(Buck Converters). I had trouble understanding the operation of the circuit as it wasn't explained properly in the book. When I looked up on the internet , ...
637 views

### 0-24V 0-47A DC-DC Converter

I have built a 12/24V 47A DC Power supply following this guide. It works well for running my battery chargers, but I'd like to make it a CCCV supply from it for my projects. What would it take to ...
259 views

### LTC2498 Temperature Sensor Chip Code via SPI

I would be very grateful for your tips for my present problem definition: I have a microcontroller ATmega128RFA1 with integrated Zigbee with UART-USB(TTL Converter) attached to the PC. From the ...
629 views

### Is there a rectifier scheme for tri-phase which is more efficient than the bridge rectifier?

Because of the topology of tri-phase bridge rectifier, every phase is active (i.e.; feeding the load) only for 33% of the time. It feels like we are not fully utilizing all the three phases, and ...
180 views

### cable losses per meter (voltage > 400 and frequencies [50 Hz … 60 Hz])

If I compute I * I * R I obtain the loss of the conductor in Watt. Is this per meter similar to the dielectric loss (see IEC 60287-1-1)? I am also wondering about the loss factor of sheath and ...
2k views

### Shorting neutral and earthing trips MCB [closed]

I live in India (220-250V, 50Hz). I have a single phase supply coming into my home. The main MCB trips as expected whenever the Live and Earth conductors get shorted. But I observed that my house's ...
8k views

### Why is flyback air gap needed for energy storage?

Why do so many sources say something along the lines "since a flyback transformer stores energy, an air gap is needed"? I have seen this reasoning in textbooks and app notes. I thought air gaps ...