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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156 views

Auxiliary circuit to reduce power losses in idle stage of this oscillator (wireless power application)

I am trying to implement the following resonant oscillator for wireless power transfer application. There will be a secondary coil coupled with Lp. . Reference - WPT Application Note One of the ...
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1answer
319 views

Why would someone prefer halfwave rectifier over bridge rectifier? [duplicate]

The other day, out of curiosity I was measuring the current wave shape of a laptop charger. The wave shape indicated a spike only in one half cycle. I'm guessing half wave rectifier here. One thing ...
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2answers
1k views

MOSFET body diode conduction

Does the body diode in MOSFET conduct current in backward direction when the MOSFET is switched OFF? If yes, can we build rectifier-bridge using 4 non-driven MOSFETs?
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488 views

Mechanical Switch in parallel to the Micro Controller working in Sync

Here is the image for my requirement,want to operate Load Lamp of 230V AC with Mechanical Switch in parallel to Controller where one can 'ON' the Load Lamp from the Mechanical Switch and 'OFF' from ...
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2answers
159 views

Meanings of some symbols in electronics

I am new to electronics and i want to get about what do the symbols encircled in red signify? Can anyone tell me what is happening in the diagram. Please help me. Regards .png
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3answers
6k views

SMPS: What is current mode instability (aka “sub-harmonic oscillation”)?

In peak current controlled switching power supplies, there is a phenomenon called “current mode instability” aka “sub-harmonic oscillation”. What is that? Can't seem to get a good explanation of this.....
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3answers
838 views

Working and simple applications of PLL [closed]

Recently I am studying about Phase Locked Loop. My professor said that it is an amazing device with a variety of application. I understood the basic working of a PLL. But I couldn't appreciate his ...
2
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2answers
724 views

IGBT transistor with auxiliary emitter

Recently I discovered, that some IGBT transistors in IGBT modules have the second pin for an emitter, called auxiliary emitter. In the picture above 2nd and 4th pins are auxiliary emitters. This is ...
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2answers
399 views

Logic-level converter FET

I have been using the BSS138 level converter circuit for a while now and today it struck me I get how the voltage is stepped up by the FET or the BSS138 when you are applying say 3.3 V on the LV side. ...
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3answers
2k views

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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2answers
422 views

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
3k views

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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3answers
436 views

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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2answers
61 views

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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2answers
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
426 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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2answers
286 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 ...
2
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1answer
948 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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3answers
31k views

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
96 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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3answers
131 views

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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2answers
361 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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3answers
9k views

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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2answers
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?
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1answer
233 views

Why is the output from this regulator not a constant DC?

I have built a link switch. The output is DC 5V but, when measured with an oscilloscope, itis not constant. Why does this happen? How do I get constant DC output? Any design problem? ...
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1answer
224 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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2answers
194 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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2answers
179 views

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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2answers
288 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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2answers
171 views

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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2answers
526 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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3answers
2k views

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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2answers
1k views

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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3answers
2k views

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
551 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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6answers
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 ...
2
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2answers
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 ...
2
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3answers
7k 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 ...
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1answer
1k views

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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3answers
74 views

Why are core losses mechanical and not electrical in an AC power flow diagram? [closed]

The power flow diagram of a generator (a) and a motor (b) are shown. But why are core losses mechanical losses?
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4answers
63 views

Isolated Power Supplies for Inverter Gate Drivers

I am using a 3-Phase IPM IGBT Inverter Module in motor driver. This module has built-in gate drivers which require 4 Isolated power supplies for their operation. In all I have to design 5 Isolated ...
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3answers
187 views

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
98 views

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
293 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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1answer
53 views

What kind of PMIC is this?

I found this circuit in a schematic I'm reviewing, which supposedly provides a regulated +5 V supply. The primary side of the transformer includes a flyback controller that switches ~340 VDC on the ...
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2answers
761 views

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
456 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
168 views

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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2answers
159 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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3answers
389 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 ...