Was surprised how hot the L7805 was getting supplying only a few mA of current. Was less surprised when I discovered that I had it installed backwards. Don’t think it’s intended to be installed with 12V supplied to the output pin. ☺

Darren Hart November 06, 2014 10:09

Surely the smoke got out?

Michael K Johnson November 06, 2014 10:27

Only got to 125°F. No chance yet to turn it around and see if it still works but I have extras. It’s not strictly necessary in my application (the 555 behind it can take 12V); I just was hoping to reduce power draw from the 555.

Michael K Johnson November 06, 2014 20:13

Holes were too tight to desolder effectively so I cut the legs and pulled them out individually, and installed a new one. It now runs cool.

Before I discarded the physically mangled part I tested it and determined that it still contained at least some of the magic smoke; 12V in and 5V out.

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