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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.

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How Long Will This Battery Keep My Fridge Powered For?

I have an interesting mathematical/electrical dilemma and I'm not sure where to start. I am considering buying this fridge (specs on page). I will be hopefully buying a battery pack with it to ...
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What does it mean that a resistor has value of 56E?

I found on one schematic that has resistor with value 56E. I don't know what does that mean. Can you give me some information, please.
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What is the technical name for fan that produces electricity?

I'm wanting to create a wind powered LED similar to this one, but weather proof. I know there's tons of them out there, but I'm wanting to build it from scratch. My issue is that I'm completely ...
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Can I drive a three phase induction motor with this method?

I have an idea to drive induction motors in a new way. I call it Variable Torque Drive (VTD). You are all familiar with VFD which utilize variable frequency and try to keep the torque constant. This ...
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2answers
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How to extract minimum supply voltage from the datasheets

I am relatively new to electronics and need to know What is the minimum supply voltage (Vcc) for LM1875 and for LF347 and how do I extract it from the datasheets? In LM1875 it is written that the ...
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360 views

How do designers know about kilowatt power of wind turbine generators like 1.5 MW?

Generators and transformers are always designed in kVA because designers never know about the load it will provide power to. Then how do we know the wind turbine generator will deliver 1500 kW or 2 MW ...
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1answer
412 views

Difference between Vth and Vge?

What is the difference between the threshold voltage (Vth) and gate-emitter voltage (Vge) for IGBT devices? How can I calculate Vth of an IGBT chip?
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277 views

pulse width modulation versus amplification

If I want to make a sine-wave inverter where the output AC voltage is lower than the input DC input voltage, how can I see that using pulse-width modulation will be more efficient that just using a ...
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1answer
947 views

Connecting wind generator to 12V battery without regulator

I've been doing a DIY Wind energy generator. I'm also a newbie in this field. I would like to ask what will happen if I connect my wind turbine to a 12V rechargeable battery without a voltage ...
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How to identify orphaned power cords? [closed]

We are doing a massive purge of "stuff" from home and storage. I am accumulating a large quantity of random, unmarked power cords. Some will have "Nintendo" or "Norelco" on them - so I know to go ...
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1answer
71 views

Is Inductive Kickback Protection not necessary for AC?

For DC inductive loads, typically a flyback diode is placed over the motor so that when the current changes instantaneously it doesn't have a chance to build upon the switch contact and then create a ...
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Can someone please help me with these questions on DC Chopper Circuits?

I had a quiz on power electronics and the following questions were asked: Question 1: Consider the buck chopper in Figure 1, operating at 100 kHz frequency, with the switch duty ratio of 0.5 and ...
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How can I size the DC link capacitor of a 3 phase inverter?

I have come across the Salcone-Bond paper Selecting Film Bus Link Capacitors For High Performance Inverter Applications (PDF), which shows equations for single-phase inverters. But I can't seem to ...
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356 views

5V 1A Solar panel only delivering low power

So I bought this 5V 1A solar panel that can be used e.g. to charge your smartphone accroding to the product description. When I measure the voltage using a multimeter I measured 6.9 V. A little bit ...
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why is noise always a high frequency signal ? what then is frequency of a noise?

while designing signal conditioning circuits for sensors , we design low pass filters to remove high frequency noise. why can't noise be a low frequency signal or what will its frequency be ?
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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?
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1answer
193 views

Induction heating

I was reading the working principles of induction heating and I think I understand the basics. Out of curiosity, I searched the Internet for a schematic and found one. However, the thing that confuses ...
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177 views

What is torque-ampere ratio at electric machines? How it is related with machine efficiency?

When I am reading a journal about SRM (switched reluctance machines) it said that outer rotor design has better efficiency due to higher torque ampere ratio. How it is related with efficiency?
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Can i replace 3 (parallel) capacitors 16v 1800uf with 16v 2200uf?

The motherboard model is G31T-M REV:1.0 . The circuit is for the 4-pin 12v power rail coming from the power supply. I'm replacing these because they are very bloated, It's quite a miracle that the ...
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280 views

Does the source impedance of DC-AC converter always represent losses?

This is a fundamental theoretical question about power and efficiency of AC voltage source with very low output impedance, for example, a DC-AC converter; H-bridge converter or class E amplifier. MY ...
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Why the implementation of current sensing network (CSN) by sensing the switch current is simpler than that of sensing inductor current?

The excerpt below is from the book Pulsewidth Modulated DC-to-DC Power Conversion: Circuits, Dynamics, and Control Designs by Byungcho Choi. It looks a bit long but my main question is why the ...
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515 views

What is the equation for a potentiometer with dual power supply?

simulate this circuit – Schematic created using CircuitLab Suppose we setup a potentiometer with two power supplies +10V and -10V as shown above. A digital voltmeter is setup to measure the ...
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Can a high voltage rated push-button switch be used on lower voltages?

I have a question regarding switch usage in a high voltage, very low current circuit (micro amps). Basically, we're taking the 120VAC out of the wall, converting it to DC (output can be either 5, 12, ...
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ESR in Electrolytic capacitor vs Voltage rating

I would like to know why in an electrolytic capacitor the ESR decreases as voltage rating increases. And why the current rating increases as voltage rating increases. Thank you.
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Do electronic devices consume more power when the ambient temperature is cold?

Just a casual observation: when it is winter, my personal devices such as cellphone and Ipad consume power more quickly compared when it is in the summer. But this could simply because of change is ...
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1answer
541 views

Find dBm and watts of the attenuator?

The question says "A signal of 40 dBm is passed through the first attenuator. The first attenuator has a gain of 1. The second attenuator has 20 dB output. Find the dBm and watts This is what I tried ...
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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 ...
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2answers
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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 ...
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3answers
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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 ...
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1answer
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Need for thyristors in power electronic circuits?

Can anyone tell me why are Thyristors(SCRs) used in power electronic circuits? How are they more adept at handling power as opposed to other active or passive electronic components? UPDATE: As per ...
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Current limit control using microcontroller

What I want is to open the MOSFET once the current passing through it exceeds 3A. A fuse is already being used, but more protection is needed. There are some options to do it. I could measure the ...
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2answers
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Three phase AC machine

I have encountered a three phase ac machine whose name plate contains following information: Y/360 V/90 Hz/2,3 A. I don't know whether it is an induction machine or permanent magnet synchronous ...
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2answers
223 views

Feed-forward capacitor in SMPS feedback

I was looking at the TPS63700 DC-DC inverter datasheet and stumbled across the schematic below. It is a more or less usual buck-boost inverter topology schematic, except for the weird R4 and C3 ...
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Why is it bad to have an inductive load (context: dc-dc converter)?

In the book I'm studying from Power Electronics - Mohan he says: (...) has two drawbacks (1): In practice the load would be indictuve. Even with a resistive load, there would always be certain ...
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1answer
398 views

Overdriving LEDs with high currents

I'm trying to drive LEDs for the purposes of a strobe light. I'm planning on driving the LEDs at ~60 fps, and for ~100 us pulses to provide very sharp strobe images. If the pulses are very short and ...
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2answers
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Can we replace an embedded system design with a general purpose computer or a smartphone?

I am a newbie to embedded systems design so this question might seem very fundamental in nature. I have been working as part of an Avionics team to develop an on board computing device for a ...
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150 views

High-side driver IC use of diode in the npn transistor BE

I would like to know why is used a diode between the BE of the npn in this circuit. The npn is used to boost the current to deliver to M2 gate in this bootstrap circuit. Is it maybe needed to get rid ...
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378 views

Parametric stabilizer circuit optimization for reducing ripple

We have a TV mainboard that will be used in cars. The input voltage will have lots of noise and not be regulated well. So we want to use a parametric stabilizer at the 12V input. Acumulator voltage ...
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2answers
567 views

thyristor equation

I know how does an I-V curve of a thyristor look like, but is there any thyristor equation that can represent the curve?
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1answer
182 views

Which type of amplifier has feedback? BJT, FET or both

The answer to this question is given in the picture shared but I am not able to understand the answer or rather I would prefer to say I do not agree to the answer given. So I need to know what will be ...
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1answer
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How to calculate the dead time to incorporate in the complementay PWM input to an H-Bridge designed using MOSFETs?

I am working on making an autonomous robot. Right now, I am involved in designing an H-Bridge using discrete components for my robot. I am almost done with the H-Bridge design, and want to test it ...
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1answer
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What is the rectifier's role in this AC dimmer circuit?

Here is a typical AC dimmer circuit: http://www.eleccircuit.com/wp-content/uploads/2010/09/light-ac-dimmer-120watt.jpg I just came across another variant which uses a rectifier: http://www....
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1answer
146 views

Is BJT amplifier a viable option if the design needs to be replicated without calibration?

||Sorry for messing this up the first time. This is my first post ever in a technical forum. Need to pick up the ways of the crowd. Thanks for all the feedback and help. Well appreciated|| I intend ...
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1answer
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wiring AC switch with DC led

This is a follow up to a previous question I had answered. I'd like to show the following diagram. Here, I have laid out (crudely) a diagram that has 120v-110vAC from the wall going to a push button ...
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1answer
350 views

Inverting buck-boost converter

I'm not really sure why an inverting buck-boost might be disadvantageous compared to a non-inverting converter. If the load has a particular polarity, then can't you just connect it backwards to ...
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1answer
345 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 ...
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1answer
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 ...
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1answer
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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(...
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1answer
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Energy loss by Hysteresis

I recently did an experiment aiming to verify the magnetization curve of the cores of a single-phase electrical transformer. I applied a sine within one core and I observed this one and the other one ...
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3answers
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Does Thyristor (SCR ) works for Inrush current protection?

Does a SCR ie Thyristor work for Inrush current protection in a circuit ?