[sdiy] Voltage regulator weirdness

[Peter Ullrich]

> I split 30V into +/-15V using 78/7915 regulators. The 7915/neg side works 
> fine, but the positive supply drops from 15v to 13v after a few seconds of 
> power. I've disconnected almost all the filter caps which helped keep 15v 
> for a few more seconds, but it still drops to 13v.
> 
> Any ideas? IC aint getting hot, it's kinda heatsunk.... I'm baffled..

You need about 2 volts reserve per voltage regulator (dropout voltage). 
So you need a minimum of 34V (under load) if you want the regulators 
working in regular situation....

Ciao
Peter

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                               Ing. Peter Ullrich   
	               Hardware & Software Developer  /  Electronic Musician
                               Private Homepage: http://www.ullrich.at.tt
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