I have a small circuit I'm testing - very basic.....
ATtiny85V, powered by a CR2032 (1, or 2 in parallel). It flashes a morse code sequence to a 3mm red LED, that's it.
LED draws approx 2mA when on, ATtiny draws 0.9mA in between.
I've just had it run for 240hr continuously to assess battery life, and it appeared to do well - surprisingly it was still functioning, seemingly normally, at 1.7V, although the LED was getting pretty dim.....
I wasn't using a decoupling cap in this circuit. I did note Vcc swinging about as the LED flashed.
In reading, a decoupling cap should be installed across Vcc/GND, so I'll do this - but what sort of cap, and what value? Battery life is a priority here - should I expect this to degrade battery life? (I'll test it anyway) Cheers!