Have a U1241B handheld multimeter.
Using a function generator with 50ohm output impedance to output a 1Vpp 1kHz sinewave. Then I have a simple voltage divider of 100ohm and 10kohm connected to the func gen output.
If I put the COM lead of the U1241B on the ground of the circuit (the ground lead from the func gen), the AC voltage measurement on the U1241B will be around 707mVrms for the high side (the input waveform) and around 700mVrms for the middle node, as expected.
But what I was trying to do, and though the U1241B perfectly capable of, is measuring 7mVrms across the 100ohm resistor. However, when I try to do this (regardless which node I connect the COM lead of the U1241B to), the reading goes immediately to 0.0mVrms and won't budge.
What am I doing wrong? Or, what did I forget about?