Hey guys I've built a lap timer using an atmega328pu and im trying to see how much current it draws when it's on. The atmega328pu is powered by a 7805 5v regulator and that is powered by a 9v battery.
So my problem is this: I disconnect one battery terminal and put my tester in series to close the loop and I put the setting on ma. Then I switch the timer on and it shows 0.75mA which is kewl, but when I trip the timer mechanism, (laser shining on a photodiode) then the program is supposed to go through a few if statements and then display a lap time. But it doesn't do this with my multi meter in series. It works when I connect the battery directly?