# 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.

1,345 questions
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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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### Does Thyristor (SCR ) works for Inrush current protection?

Does a SCR ie Thyristor work for Inrush current protection in a circuit ?
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### Lossless Resistor model in PSpice?

Is it possible to make a lossless resistor model in spice? I want to test the large signal model of my DCM SEPIC converter (without linearizing it). OrCad's PSpice library doesn't seem to have it, but ...
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### Transformer rectifier set. A question about the schematic diagram

This is a high voltage transformer (53kV) and rectifier that is used to power an Electrostatic Precipitator. The schematic shows a jumper between terminals H1 and H2 with a label "Remove jumper for ...
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### Junction to board thermal resistance

The Junction-to-case (bottom) thermal resistance of the TPS7A4701 LDO regulator is 1.7 °C/W. It is explained in the TI's app note "Semiconductor and IC package thermal metrics" that this metric refers ...
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### Calculating Op Amp gain with voltage divider

Is there a gain differences between schematic 1 and 2? For schematic 1, the gain would be $$-\frac{R2}{R1} = -\frac{100k}{1m} = -0.1$$ But what about the schematic 2? Schematic 1: simulate this ...
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### AC Motor flyback diode

Both AC and DC motor are inductors, and flyback diodes are used to dissipate residual current when power is disconnected from the motor. Flyback diodes are always present in DC motors, do you need a ...
368 views

### What is the name of this DC-DC converter topology?

I spotted a circuit in the wild that generates symmetric (e.g. ±8 V) analog power rails from a single +5 V supply using a single boost converter and a single 10 μH inductor. This is a very ...
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### BTA16 absolute maximum amperage at 220/240V 50hz and impact of snubbers on resistive loads?

Using a BTA16 600CW3 triac with the arduino uno with the following schematic. Can it derive a 1.5 ton Air Conditioner and what is the absolute maximum amperage and power it can handle safely at 220/...
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### What does 'g' in switching converter input voltage $V_g$ stand for?

I'm studying switching converters and the input voltage of a Buck, Boost, or whatever is designated as $V_g$. I've racked my brain (and also searched Google), but I can't work out what the 'g' could ...
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### Low power chopper and power inverter

I'm seeking advice for components I could use in my lab course. My goal is that my students understand experimentally the ideas (circuit as simple as possible) behind a chopper device and a power ...
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### Design considerations for a high voltage boost converter?

I'm trying to figure out the best method to get around 200V @ 15mA from a LiPo battery, and had a few questions. Should I be converting down to some voltage (eg. my microcontroller supply rail) with ...
787 views

### Better to regulate voltage by supplying or subtracting base current to BJT pass transistor?

As a learning exercise, I'm designing new guts for one of my venerable HP 721A (circa 1959) DC bench power supplies. With help from members of this site I was able to vastly improve the reference ...
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### Question regarding a resistor in optocoupler/TRIAC circuit

I'm building a ac motor starter with a optocoupler (FOD4218) and a TRIAC (BTA16), one for each phase in a three phase 400V system. I have a question regarding the circuits that can be found all over ...
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### First steps in building Switching power supplies

I want to make a 50Amps switching power supply, I have already done 10A linear ones succesfully This time it has to be a switching power supply one so, any ideas or tips of where to start are ...
828 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 ...
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### 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 ...
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### Quarter-wave impedance transformer working principle

consider the following scheme: A transmission line of length lambda/4 has been put before the load ZL in order to get an impedance matching. But, I do not understand how it works. Precisely, by the ...
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### 3 Phase PMSM Motor Current Measurement: Figuring out the 2 negative terminal currents with 1 positive current measurement

I am trying to implement F.O.C for a PMSM machine with a custom made inverter board. The H-bridges are from Infineon (IFX007T) and they provide current sensing capabilities. The problem is, i need the ...
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### [Last Update]Simulating an RLC circuit with the 1N3880 in ngpice did not show any results or graph

Im trying to do a transient response analysis with ngspice/gnucap and gspice UI of the next RLC circuit (corrected the source polarity), to find the damping effect in the system. That with the next ...
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### Distribution-side voltage regulation and Low voltage ride through (LVTR) curve

Nowadays, I see that photovoltaic systems have Low-voltage-ride-through capabilities. So in case of a fault, when the voltage is decreased, they remain connected to the grid and provide reactive power ...
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### How to deal with “peaks” voltages in mosfet in boost converter?

I'm designing a Boost Converter to go from 5 [V] to 12 [V]. The design I came with is the following: To understand better the design, please note the following: 1) To drive the mosfet I'm using a ...
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### How do MPPT charge controllers curtail the power if the load is less than the solar generation?

I am trying to understand how MPPT charge controllers work when the load is less than the solar power generation. Let's assume an off-grid system with battery backup and no dump load. In my ...
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### Driving a 12VDC solenoid from a 24VAC signal

I would like to put together a circuit that does the following function: 1) You input 24VAC. 2) It outputs 12VDC pulse to drive a 3W, 4Ω latched solenoid. 3) Once 24VAC is removed, it outputs a ...
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### what does offline mean in flyback topology [closed]

What off-line means in flyback converter. is there any online also. if yes please describe
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### High-Speed electronics - Reflections in T-intersection

I'm currently attending a course on "experimental problem solving" and we just started talking about TDR (time domain reflectometry). I do understand that reflections occur whenever there is a change ...
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### Uncontrolled Bridge Rectifier

I am getting wrong answer for the above problem. My book says R should be 23ohms. Please guide me where I am doing the mistake.
2k views

### How sinewave pwm inverter filter output?

I know about inverters is as follows (correct me if I am wrong) DC source such as battery fed current into transformer by controlled switches such as mosfet or IGBT. This controlled current fed into ...
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### Help with semi-controlled full wave monophasic rectifier using MOC3011 and SCR

I'm trying to build a full wave semi-controlled rectifier with this circuit: The zero's detection is working well and I am firing the TRIAC depending on the position of the potentiometer, the ...
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### Mosfet Conventional current flow direction in the circuit

I am working on a project to control heavy loads with Arduino up to 10 Amperes. I found the circuit which is made using p-channel Mosfet and a p-type transistor. I am confused in the flow of current ...
359 views

### How to define working voltage class net to calculte the creepage?

I work of a project of single phase PFC converter and I need to define the working voltage to each each NET of Schematic to calculate creepage distance. I have a question about the low voltage of NET ...
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### freewheeling diode needed?

For a BLDC driver I`m using this Mosfet: http://www.farnell.com/datasheets/526719.pdf?_ga=1.38505579.956125949.1445440291 on page 6 there are some diode data. Is this diode enough for my application? ...
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### Designing a High-Voltage Bidirectional Square Wave

I want to create a signal to send through an electrode that my senior design group is designing. The signal is very well-defined because our electrode is going to be compatible with a very specific ...
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### Driving a fan using a mosfet, do I need a diode?

I am using this BS170 MOSFET to drive a fan using a pwm signal generated by a 3.3V MCU according to the following schematics: (I know about the wrong symbol it's just for the packaging on the PCB) ...
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### Boost converter help

First, the problem I am trying to solve: My objective is to create a device that will generate a constant current to a load that varies in resistance from approximately 1Kohm-40Kohm. I will be using ...
552 views

### What is the difference between capacitive fault currents and resistive fault currents?

http://uk.megger.com/battery-ground-fault-tracer-bgft\ This website claims that it's product can differentiate between these two fault currents. But I don't know what the difference is.
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### How to power ESP8266 from changing voltage

So I'm very new to electronics of all sorts, have done some basic repairs but I'm interested in learning more. The project I have in mind is to use the cheap and easily available Doit NodeMcu Lua ...
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### Why does a triac trigger with gate current in either direction?

I've been coming up to speed on thyristors, and triacs in particular. I've found detailed material on them a little hard to find, in particular on the device physics. Horowitz & Hill is silent on ...
1k views

### High step up DC-DC converter switch mode power supply

I tried to design DC-DC high step up isolated single switch converter and simulate it in Proteus 8 professional, that design have a gain reached to 20 if that possible? and I confused by one thing, I ...
884 views

### Isolating high voltage/high power electronics from low power electronics

I understand that galvanic isolation is necessary to prevent shock and injury, but I don't understand when (or if) it is necessary to isolate the high voltage/high power side of a circuit from the low ...
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### Buck regulator to match an analog voltage

In desktop computers, it's common to have headers that control fans with a 0-12V analog output, capable of up to 1A. This works fine for one or two fans, but with more than three fans, you can exceed ...
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### A circuit having 2 inputs and 2 outputs

I am going to design a circuit that should have 2 inputs and 2 outputs. when both inputs are low both outputs should be low when input 1 is high and input 2 is low, output 1 should be a square wave ...
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### half bridge IGBT not switching high side on

I have designed a PCB with a FAN73933 half bridge driver. It is designed to drive 2 IGBTs (FGH40N60SMD) with +- 170V rails. I have attached a schematic for better understanding. The problem is I can ...
646 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 ...
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### Protect Inverter from Transformer's Inrush Current

Consider a "small" autonomous grid, which is based mainly on RES and has a few diesel generators, like in the following figure Everything runs smoothly, feeding the small load. Suddenly, the big ...
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### How does a electropermanent magnet work?

I’m trying to wrap my head around electropermanent magnetism. I read this wonderful PhD Thesis by Ara Knaian as well as details the history of this concept as well as Kyle Gilpin, Ara Knaian, and ...
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### How can charging current be understood intuitively?

The charging current I’m talking about would be the one between un-shorted phases and ground when there is a short to ground in one of the phases in a distribution network or facility. I'm not talking ...