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Bruce Esquibel[_2_] Bruce Esquibel[_2_] is offline
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Default LM317 Votage Regulator Instability?

Phil Hobbs wrote:

What's flaky about the 317? You can blow them up by overvoltage, or by
pushing a large current backwards into the ADJ or output terminals, but
otherwise they're pretty well-behaved. Well, they will oscillate if
you're running at low gain and you put 10 nF on the output. However,
it's a 1-A class regulator, and just about any circuit needing anything
like that much juice will have a lot more capacitance than that.


Well, for all the reasons you mentioned and the fact this thread is like
2 or 3 days old and the OP still hasn't made it work.

I know the 317 is probably the most common regulator used but just isn't
the best choice in some cases, like this one. Cost I'd guess is the best
reason to use them.

The LM78xx (and LM79xx for negative outputs) are far simplier to use at a
slightly higher cost. They have excellent ripple rejection, thermal
protected and short circuit protected. Usually except for a .001 cap they
don't even need a heat sink (current dependent of course) for the TO-220
package.

Even if they need a heat sink, the tab is ground so you can just nut/bolt
it to the chassis (provided it's at ground which is usually the case).

in-gnd-out is it, no fuss, no muss.

-bruce