Quote Originally Posted by ath View Post
Make sure, that the Battery is not only 1.5V but also silver. Alkaline is not stable enough for this. AFAIK the PX625A is alkaline.
That's a good point. Your lithium cell idea looks more promising now. Not necessarily with a regulator though. I may do some experiments with an LED in series instead of the schottky diode. A 1.7v drop with a 3v cell = 1.3v so it could work.

I know the regulator is the most accurate approach but I also like to think in terms of simplicity.