Battery monitoring - ever tried AN1072?

[flotulopex]

Thanks George,

The aim of the thread I started is to find a good solution to check the battery's condition regardless with what PIC it is used.

In my case, I'm building a cooking timer and I have a sounder that needs at least 5VDC. So I'll better know when the batteries get low or my eggs will be like stones

[Ioannis]

Hi Roger.

I like my egg like stones, but thats just me...!

About your circuit, you put a transistor I suppose to conserve energy while not measuring the battery, right?

But when the transistor is OFF, you drive a PIC input at 6 volts, higher than the specs, and also higher than the Vdd supply. So, the protection diodes of the input will forward the current to the PIC Vdd pin and you fry your PIC than your eggs!

Ioannis