Hi Again,
phone working with LM317 @ 3.75v. It's the TO63 package so it lies flat on a copper area of a PCB.
Should there be a large amount of heat generated by the LM317? I've got a piece of old PCB (2.5 x 4 cm) soldered to the back of it to dissipate heat.
I can only just touch the LM body - it's that hot! Although I note from the datasheet it can operate up to 150 deg C, above which it has built-in thermal shutdown.
I also noted the size of the heatsink on electroniccircuits.com's website.
Do I just need a bigger heatsink, I wonder, or could there be a more sinister problem?