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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.

76
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11answers
23k views

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?
2
votes
1answer
148 views

Full Bridge VSI problem

The above problem was asked in GATE(Graduate Aptitude Test in Engg) 2015 in India. I have no idea where to start so I can't show my attempt. But through google, I got solution by 2 different coaching ...
14
votes
3answers
33k 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 ...
0
votes
1answer
3k views

How is the gate trigger resistor value calculated for a triac

As per the application notes of bta08-600cw, to control a three phase induction motor, for triggering the triac gate, the value of resistor is shown as 510 ohm. How is this value arrived at? What ...
12
votes
4answers
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 ...
3
votes
3answers
977 views

Why do we want higher power factor in ac motors?

Here is a simplified 3P electric motor below: This motor is simply combined of three coils facing toward to the rotator (in the center) 120 degree apart to each other. The user wants his rotator to ...
8
votes
8answers
70k 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?
3
votes
1answer
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). ...
0
votes
2answers
992 views

what the best way to calculate Rg gate driver for Mosfet

I need to drive a MOSFET IPW90R120C3 from Infineon here the Specification of MOSFET VDS @ TJ=25°C 900 V Rdson @ TJ=25°C : 0.12ohm Qg = 270nC Specification of ...
4
votes
2answers
481 views

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 ...
2
votes
2answers
2k 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.
1
vote
2answers
2k views

TRIAC Angle of Firing vs Power Delivered to Load, how calculate?

I'm building a phase control system for simple power control to a given load (heater for example). I need an equation to find the relationship between angle of TRIAC firing vs power delivered to load ...
1
vote
3answers
749 views

IR2110 max duty cycle

I'm using the high side of an IR2110 driver. If I set the duty cycle to 100% the circuit burns out, I haven't how can I calculate the max duty cycle for the driver in a given circuit?
1
vote
3answers
801 views

How to use the same antenna to receive and transmit on the same frequency with an SDR [Half-Duplex]?

Considering that the SDR board has one TX/RX output/input and one RX input, I am wondering how could I use one antenna for a half duplex communications on the same frequency. The idea is to use the ...
0
votes
1answer
81 views

can you explain me the working of this circuit in detail? [closed]

this circuit is a occupancy light circuit i want to know the working of the transistor regarding base,collector and emitter in the transitor
4
votes
5answers
15k 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 ...
2
votes
4answers
176 views

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 ...
1
vote
1answer
307 views

Capacitor Voltage Rating

How to find the voltage rating of a capacitor after knowing the capacitance value. Example, For a power supply, If the input voltage is 60V and output is 5V. The input capacitor(C1) value is 100uf ...
1
vote
1answer
579 views

High power pulse generator

I'm designing a relatively high power pulse generator. Basically I have a microcontroller generating a clean square wave (0-3.3 V or 0-5 V) which then goes into my amplification circuitry. I want to ...
0
votes
3answers
288 views

Resistor values for a Voltage- Controlled Current Source Circuit

simulate this circuit – Schematic created using CircuitLab Hi Folks, During my bachelor thesis, I am learning IGBT gate driver cricuits. I am struggling with understanding the following ...
0
votes
1answer
308 views

Hacking DSLR battery to power camera from power supply [closed]

I would like to power my DSLR for long captures with a power supply. I know the voltage and inner structure of the official batteries. The battery has 2x 3,7V cells inside with a circuit. People ...
-1
votes
1answer
160 views

Why does a wind turbine deliver reactive power to the grid during no winds or when turbine is stopped?

An answer to a previous question explained that a turbine in stop mode may deliver reactive power to the grid. It also takes active power from the grid to run its control system, lighting system and ...
-2
votes
1answer
178 views

Maximum power transfer and Thevenin

I am trying to find the thevenin resistance value and the Vth for maximum power transfer. I have tried to find Rth by calculating R3 and R2 as parallel resistance and same for R4 and R5 and then ...
-6
votes
1answer
114 views

Explain the equation [closed]

Explain the following equation... $$ r^{\prime}_d = \dfrac{26\mathrm{mV}}{I_D} + r_B $$ Explain from where and how this equation comes out . Also elaborate the terms used in above mentioned equation....
33
votes
8answers
5k views

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?
6
votes
3answers
6k views

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 ...
13
votes
2answers
3k views

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 ...
5
votes
4answers
19k views

Arduino 230v Light bulb dimming

Hey guys i have done a lot of research and testing on different circuits for 230v(50hz) or 220v light dimming, but i cant get my arduino to dim my light. This is the last thing i tried. made this ...
5
votes
4answers
12k views

Parallel MOSFETs and Gate Drive Capability

I'm trying to design a Full-Bridge which can handle upto 330 A (@ 12V). I'm paralleling 3 MOSFETs per leg, and I think I've found a low enough RDS(on) MOSFET to make this somewhat practical. Here's a ...
5
votes
1answer
28k views

Q-Point of a circuit

In a BJT or MOSFET circuit we have this curve: What is that q-point? From my research I have the following information: The operating point of a device, also known as bias point or quiescent point ...
3
votes
3answers
13k 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 ...
-1
votes
1answer
568 views

STPM34TR multimeter IC

Hello I am working on a project that requires utility grade metering, and so we using the STPM34TR. The hardware is working and we have looked over the datasheets, the internet and anything else we ...
5
votes
3answers
2k views

Generating electricity by moving a door

I'm entirely new to electrical engineering. This is for a hardware/software project I have in mind, where I need electricity without having to plug the device into a power source. My intention is to ...
3
votes
1answer
883 views

How does this FM transmitter work?

I'm an electronics student and I have been trying to understand this FM transmitter diagram (taken from electronicshub.org) for a long time. I had put efforts to learn it by surfing the web but parts ...
2
votes
1answer
2k views

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 ...
1
vote
1answer
869 views

Which informations do I need to calculate the efficiency and horsepower of a 3 phase induction motor?

As far as I know the magnetic force is responsible for the motor rotation. So, horsepower of the motor is mostly related to magnetic flux on the coils (windings). Also magnetic flux is directly ...
1
vote
3answers
5k 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.....
1
vote
1answer
392 views

Transformer dimensioning for SMPS (not the Aw Ae way)

There's a lot of documents that talks about dimensioning of the transformer for a SMPS power supply (in this case one quadrant only is not of my interest). this site cites the following: The main ...
5
votes
2answers
2k views

Induction heater circuit problem

I am trying to build induction heater with the help of the following schematics(taken from this page): So I am using 220:10Vrms(15Vpeak) transformer with fullbridge rectifier and a capacitor to get ...
4
votes
5answers
3k views

How to control power to a water heater

My water heater element is rated at 3.6kW at 240V. To use solar power efficiently, I would like to use excess solar power (in a grid-tied arrangement) to heat our domestic hot water. Our electricity ...
3
votes
6answers
870 views

Does output voltage of a boost converter depend on load current in CCM?

In the thread below, there are different opinions whether output voltage of a boost converter operating in continuous conduction mode (CCM) depends on load current or not. Boost Converter Output ...
3
votes
1answer
1k views

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....
3
votes
2answers
464 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 ...
3
votes
4answers
198 views

Burning a Power MOSFET

We are doing battery heat testing and want to be able to vary the current in the circuit to different test points up to 100A. Our circuit schematic is attached. The MOSFET is IXFN360N10T. We attached ...
3
votes
3answers
1k views

Voltage Spikes in MOSFET H Bridge

As a part of my effort to build a pure sine inverter I made the following MOSFET H Bridge. This was connected to a load through a LC filter where PWM signals are given as in the diagram below.PWM ...
2
votes
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 ...
2
votes
2answers
353 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 ...
2
votes
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
votes
1answer
273 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 ...
1
vote
5answers
922 views

How to test the maximum secondary current of a step down transformer?

I got a small step down transformer from my local market which has a total of 6 individually isolated winding in it (1 primary of 230V and 5 different secondary wingding with 5 different voltage). My ...