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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Where does electricity go after being used?
For a very long time I have been wondering, where does electricity go after being used? When I use my tablet it runs from a battery. Where does the power go?
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Weird resistor with dots around it on the schematic
I was looking through the LTC4041 datasheet and saw this:
The 10mOhm resistor with the two nodes really close to it - is that a "special" resistor or something? Why have they drawn it like that?
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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?
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Why do devices stop operating properly in extreme cold?
I have noticed that a lot of smart phones say that they won't operate under -4 degrees F (-20 degrees C). Can anyone explain to me what happens when the phones get cold that stops them from operating?
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Why does power dip during a lightning storm?
If lightning were to strike power lines, wouldn't you expect it to increase the power, and hence your room lights get brighter?
Why do they go dim for 1 second at a time?
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Spacecraft Power Supply Frequency
I know that aircraft sometimes employ a 400Hz AC system to save weight on transformers, so I'd imagine that spacecraft might employ a similar technique. I'm wondering if anyone in the aerospace field ...
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Are all electrical sockets of my house in the same phase?
Most countries use AC power that is supplied to each house. This AC power is in the form of a sine wave. Suppose I have 2 electrical power sockets in two rooms that are at the opposite ends of my ...
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How do I find the voltage range for an unknown DC motor?
I have a small unmarked motor with a burned out speed controller board. I'm able to figure out that the motor is a DC motor because it has two wires coming out of it and there's a rectifier on the ...
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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 ...
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IGBT vs. Power MOSFET for switching applications. Where to draw the line?
For lower breakdown voltages, a power MOSFET is clearly the device to go for, in view of its higher efficiency, higher commutation speed and lower price.
Where should the line be drawn, upwards of ...
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PC ATX12VO (12V only) standard - Why does everybody say it has higher efficiency?
To my understandings, the new 12-volt only standard moves the 5V and 3.3V supplies off from the ATX power supply "box" to the motherboard.
According to PC World (which is cited by Wikipedia),...
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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 ...
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Why an electrician wiring error could make a PC's USB shield be at 120V when it should be grounded
I almost had a serious electrical accident last week when I was trying to use an oscilloscope to test out a circuit a student had built.
I had the scope plugged into a floor outlet, and the circuit ...
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Voltage regulator from first principles - why is power dumped in the transistor?
I'm trying to further my understanding of electronics, so I decided to try to design a fixed voltage regulator capable of supplying an amp or so. I put this together from first principles without ...
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How To Know If a Fuse Will Work Properly?
I want to know what kind of periodic test we use to test if a current-limiting fuse will normaly open and protect an electronic circuit (a battery charger) if a failure occur (short circuit or over ...
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What does a black bar across transformer symbol designate?
What does a black bar across a transformer symbol designate?
This appears in a power electronics context, and in particular in this case with substituting a DC transformer as an equivalent circuit ...
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What kind of hardware implements Fourier transform?
I looked around online but I found nothing relevant. It is very difficult for an electronic device to decompose a signal in different frequencies.
How this is done at the bare metal level?
Any ...
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Symbols: Double-arrow circle enclosed "10" on electronic appliances
What does the symbol that says 10 inside the double arrowed circle mean? I have seen a similar symbol on another appliance that had the number 25
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Why/when is AC-DC-AC conversion superior to direct AC-AC conversion?
I am currently studying wind power and the power electronics used for it. In wind power a generator is driven by wind, thus the resulting power is of widely varying frequency and amplitude. The power ...
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Why does converter's efficiency degrade with higher V_IN?
Please consider the following efficiency graphs of the exemplary MP2384 buck sync converter:
What I am trying to understand is why is the efficiency at light loads worse for the cases in which the ...
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Why do power diodes have a p+ n- n+ construction and why not p+ p- n+?
I've been learning about power diodes and how they differ from low power diodes with the addition of a lightly doped n-type layer.
This n-type layer improves the breakdown voltage rating of the ...
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How do people prototype circuits without getting shocked?
I am just getting into soldering, developing prototypes on perf boards and microcontrollers. The current for some can be as high as 2 A. I am trying to build a drone and the BEC for one ESC is 5 V and ...
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Which method or component is best to regulate 42 to 3.3 V?
I am using a 36 V battey pack (10s 2.5 A each cell 3.6V.) Its maximum voltage is 42 V. I am using a STM32 microcontroller whose input is 3.3 V.
I am designing a PCB in which the power supply is drawn ...
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Discharging one side of a capacitor?
What I'm asking about is if it's possible to discharge one side of a capacitor. I've found a question about that, but I also found the answers to be a little unclear or questionable. I imagine that ...
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What happens if I connect a low voltage rated capacitor to a high voltage?
Given that c=q/v even if I connect it to a higher V, its charge Q may decrease proportionally right? So why should it damage my capacitor? or will the internal electric field get too high and cause ...
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How to shunt 1500 joules when voltage exceeds 75 VDC
I have an alternator that charges at ~58 V at 100 A. If its load (a lithium bank) cuts out suddenly (bms cutoff), I need a way to shunt power for 200 ms to a dummy load to prevent the current from ...
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What is the difference between CPU transistors and generic ones?
Recently I had to build a h-bridge driver for my project, wireless power transmission. I learnt that I needed to have dead-time in my PWM signal given to IR2110, which doesn't have any dead-time ...
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LM386 amplifier circuit
I am building an audio amplifier with LM386 with a voltage supply of 5 V.
The input signal is 50-250 mV.
Can anybody tell me why there is a resistor and capacitor in series at the output?
As the value ...
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Will a battery short out when the terminals are directly connected together or will internal resistance save it?
I intended to make a simple electromagnet, then I saw this video where the user is connecting wires together with no resistance at all. I was wondering why it doesn't short out and make the battery ...
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Parallel decoupling capacitors: Is inductance reduced?
Background
In general, when placing decoupling capacitors in parallel, their capacitances add and their compound ESR is reduced (like for parallel resistors). But I am a bit uncertain if/how this ...
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Overvoltage protection circuitry choice
I need to design a input overvoltage protection for a 45 W DC-DC converter rated for a 9-24 V wall wart input (so, 45W/9V = 5 A input current at max). So far I've seen two approaches (schematics below)...
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Is it safe to simply cut the power to an electronic device instead of using its power switch? [closed]
I have a pair of powered studio monitor speakers for my PC. Each speaker has a dedicated on/off power switch on the back. It's inconvenient to reach around behind the speakers to turn them on and off ...
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What are the best old electrical appliances to extract electronic components from? [closed]
I would like to build some simple drones and robots which I will be controlling using a microcontroller. Instead of buying expensive brand new components, I prefer to look for old electrical ...
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Isn't current flow a wrong term?
In most text books and other electronics material it's said current is flowing through the circuit. Isn't this wrong? As current is flow of charge. Is there anything such as flow of flow of charge?
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What is a good power electronics textbook? [closed]
I really want to learn as much as I can about power electronics, switching mode power supplies, and overall analog design. Unfortunately my universities computer engineering program is still ...
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Software suggestions for electronic simulations?
I am a beginner in EE engineering and want to use a software where I can analyze signals or even motor speeds, power electronics ect. But the Spice programs looks so boring and detailed for me. Maybe ...
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dual of voltage doubler
Voltage doublers, like those close to be one stage of Cockroft-walton multipliers, are well known. They allow to double the voltage of an AC input and can be useful at the output of a transformer for ...
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Why is it desirable to inject reactive power into a transmission system?
This website explains the basics of FACTS technologies and how they can be used to exchange active and reactive power with the transmission system, namely:
SSSCs - can exchange active and reactive ...
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What is this high power switch symbol?
I am a medical physicist, and I program software for MRI scanners as well as develop electronic devices that interact with them. Because of the way MRI works, it is necessary to use very large power ...
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Why do we allow discontinuous conduction mode (DCM)?
I know that DCM occurs when ripple is greater than the DC component, but why would we allow ripple to be greater than the DC component? Don't we see ripple as something undesirable and try to minimise ...
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What is ORing and why is it named ORing?
I read some documents like the PoE application, it used ORing to protect the reverse input current. I would like to know what ORing is. I googled it, but I cannot find the answer. It seems like a ...
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STM32 - How does analog configuration of MCU pins affect the power usage?
When I was creating a new project using the STM32CubeMX, I saw a check box stating that setting all free pins as anlog will decrease the power consumption. I couldn't figure out how it works. How can ...
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What's the easiest way to prevent a voltage input getting higher than a fixed value?
I just got a DC-DC step-up converter for my laptop, and I want to make double sure in case it malfunctions it will never affect my laptop. I am looking for an extra security device to prevent the ...
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Reason of using a resistor parallel with NTC at mains input
I have a SMPS circuit. There is a serie connected NTC at Neutral input. I know NTC is used for inrush current limiting purposes. But there is a 20ohm 2W resistor which is parallel this NTC and I don't ...
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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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Bench power supply with no minimum output voltage
Just like many other electronics hobbyists, I am trying to build a variable bench power supply with 0-30 V and 0-5 A output.
I have gone through various sources to get a basic idea of how to design ...
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Role Of Emitter (By Pass) Capacitor
What is the importance of Bypass capacitor of Common-emitter amplifier? Will the gain be reduced when it is removed?
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Derating of C0G DC block capacitors with applied DC voltage
I was having a discussion with a colleague at work regarding derating of MLCC capacitors when used as a DC block capacitor. My colleague mentioned that it is standard practice to derate MLCCs with the ...
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For a MOSFET, does capacitive gate current only flow through to the source?
Everywhere states that a MOSFET has no current at the gate. However, this is not true since, during the time the gate capacitance charges up to reach the certain voltage threshold, the current is ...
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Regarding Ferrite Bead
What is a ferrite bead? How is it different from an inductor? How is it rated? What are its important parameters? What allows me to chose between an inductor or ferrite bead to filter out frequencies ...
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