Re: LM317 exploding electro
- From: "Ancient_Hacker" <grg2@xxxxxxxxxxx>
- Date: 7 Dec 2006 05:46:05 -0800
John Morris wrote:
I know someone is going to make me feel stupid for asking this, but
...
I have built the standard LM317 PS circuit with variable pot, etc. on
a solderless proto board. Input is 37VDC from a plugpack.
It works fine for about 20 seconds, then the 10uf 63V electro in
parallel with the pot heats up and explodes.
I have checked the circuit a dozen times and cannot find a fault.
Can anyone offer a clue? I have heard some brands of LM317 have
differing pinouts.
Thank you,
John Morris (the moron)
There's no way that should happen. Even if you get the electrolytic
backwards, the adjut pin on a good LM317 only supplies 1.37 milliamps,
which is unlikely to blow a capacitor in 20 seconds.
Use your voltmeter and check that the LM317 is getting a PLUS voltage
to its pin 1 (the leftmost pin). Not Minus. Not AC.
My bet is it's AC.
.
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