Really dumb regulator question

Othersider said:
So these are rated at 1A.

http://www.mpja.com/productview.asp?product=0361+RG

Can they (like 25 of them) be paralleled to give a 12V power supply with 25A capacity? Basically would it just involve joining all the Pin 1s together, all the Pin 2s together, and the Pin3s together (with adequate heatsinking of course)?
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No, you can't parallel LM78xx's - they can oscillate or worse if you do.

Describe what you're trying to create - input voltage, output voltage and what it's going in...
 
There is a way to use a power transistor to increase the current capacity of a single lm78xx regulator described in the datasheet. However, it would be a challenge to make it work at 25A because you'd need a very large transistor on an even bigger heatsink.
 
i paralleled two to get double the current last week in a lab test... it introduced alot of noise into the circuit.
 
mattg2k4 said:
There is a way to use a power transistor to increase the current capacity of a single lm78xx regulator described in the datasheet. However, it would be a challenge to make it work at 25A because you'd need a very large transistor on an even bigger heatsink.
Click to expand...
I've seen lots of big 12V, ham radio supplies that use paralled 2N3055 transistors combined with op-amp circuits... some producing 30A or more. It's possible, you just need BIG heatsinking.

I have a 50A, 12V "regulated" power supply that consists of a variac, a big transformer, a rectifier and a few big computer grade electrolytics. To adjust the voltage, turn the variac. For simplicity, price and efficiency you can't beat the thing. :D
 
the only circuit i know is this one but its just :x for 10A

but watch out. if you want 12 volt out you should use the 7815 because the MJ15004 needs 3 volts for itself. and if you make this power supply use a BIG heatsink for the MJ15004
 
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