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How to make a high amp bridge rectifier? Answered

I want to drive a peltier plate from a 12v transformer coupled with a bridge rectifier , but the diodes get very hot , so how can I make a high amp bridge rectifier that can provide upto 10 amps?



Answer 3 years ago

ooh , please stick it in your face , :)

Well, you could go shopping for some bigger diodes. In fact you could probably find the whole bridge rectifier in one package, square-shaped, with a hole through the center so you can bolt it to a heat-sink.

Regarding power dissipation, the voltage drop across a forward biased diode is approximately constant, over a wide range of current. For example, for silicon diodes, Vforward is about 0.6 volts. Thus the power dissipation is approximately proportional to current, since P= Vforward*Iforward.

For example, a bridge rectifier, rectifying 10 A, has four diodes, on half the time, or equivalently two diodes on full time. So the power dissipation is going to be roughly, 2*(0.6 V)*(10 A) = 12 W, and for that amount of heat, you probably want a heat sink, a small heat sink. Or maybe just bolt it to the side of a metal box.


thank you ! , but do you know where I can buy these rectifiers , particularly this model , Can you provide some links ?

Actually, I grabbed that image from this page,


This particular seller, sells surplus electronic parts, so their prices are usually lower than the places that sell factory-new parts. They're located in Arizona, part of my home country, the Former United States.

If you also live in the FUS, they would probably be a convenient place to buy parts from. If not, it would probably be more convenient to find a seller closer to your home country.

Big bridge rectifier like that, made to be mounted to a heat sink, and for currents greater than 10 A, is a relatively common part. There should be lots of places selling them.