Re: [uCsimm] Voltage regulator backwards?

From: Geoffrey Wossum (
Date: Sun Aug 05 2001 - 20:40:45 EDT

> Ok... the TO-220 case is the solid-state transistor-like case? I
> lined up the regulator w/ the silk screening and pulled the center pin
> backwards to go in the middle hole, then soldered it all in... I'm
> guessing that's correct?

Yes, that sounds correct.

> And yes - its VERY hot... Nearly burned my finger... I'm using a
> variable Voltage Radio Shack power supply - I get ~1.5 V from it set at
> 4.5 and 6 V. Is it possible other elements of the circuit are
> incorrect? I'm going to try to find a picture of an assembled board so I
> can double check everything. And am I correct in assuming the 0.1uF
> capactitor has no preferred orientation?

It might get a little warm, but that's definitely too hot. Check to make
sure that your power supply outputs DC, and that it is positive tip.
Otherwise, you're running voltage through it backwards.

Yes, the 0.1uF caps are not polarized, but the big electrolytic is.

Geoffrey Wossum
Project AKO -

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