I have had trouble figuring out the problem with a 5V voltage regulator
circuit I am building. I soldered it together and at first it didn't work. I
realized it was a soldering error on my part and there was a short. I got it
working and didn't think any thing of it. The next day I test it to find
that it is not working properly. There is a very small voltage on the output
of the regulator that quickly drops to
0 when I test it. Suspecting another short I use a continuity test and find
nothing. I test it many times with no results. Then out of nowhere it starts
working again. This has got me baffled. I am wondering if it could be a
fault with the regulator itself. I am sure that none of the other circuitry
and ICs are to blame. Perhaps the regulator got to hot during soldering even
though I used a heat sink. Here is the regulator circuit:


                                  _______
                             |     |
Vin      ---+-------+----|  IC1  |----+-------  Vout
                |       |    |_______|    |
                |         |          |        |
             ---         ---         |       ---
           C1---   C2---       |       --- C3
                |         |          |        |
                +-------+--------|--------+
                                   Gnd

C1 - 100uF electrolytic cap
C2, C3 - 0.1uF tantalum
IC1 - L4940V5 low drop out voltage regulator

        The drop out voltage of the regulator is 0.5V. Any ideas on what the
problem is?

Thanks

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.