I am measuring the voltage on a photocell. When I hook it up to a multimeter I get the expected result - ~0.4V when illuminated, ~0.1V when dark. But when I hook it up to Channel 0 (Differential Mode) I get two states: either the correct voltage of ~0.4V OR it locks at ~3.0V. Then it unlocks and shows the correct voltage. Then it locks again. It is possibly triggered to lock by forcing the photocell voltage towards zero, but I am not certain. Any ideas what is going on?
Thanks,
Bob
