Difference between battery and PSU

[oleoleo2]

Hello someone.

I have a small device I have put together from a small watch. It now says "beep" when the battery is connected. I want to couple it to an Atmega16 (MCU) so I can hear the beep when it restarts (by watchdog timer). The problem is: When I connect 1.5V battery it works fine, but if I make a voltage division from VCC 5V to get 1.5V to feed the thing it doesn't "beep". Why is that (not) happening?

Hope someone can help me!

 

[Nigel Goodwin]

Possibly you're using too high a value resistors?.

 

[oleoleo2]

No, I have tried to connect it (shortly) to the 5V just to check, it didn't work with that either (and it still works after that with the battery)

 

[oleoleo2]

Ok. Problem solved! If I Use a small diode in series with the thing it works! I guess it must be that the diode is limiting the current or something(?)..