Bill i read the instruction that were with the probe and i thought it was a mistake at instruction 9-10 where it says set meter to mv and gives reading as ma . SO does it work like you suggest with a resister somewhere in the probe? I just tried with the probe switched to plate current and the meter set to mv .I get a reading of 27mv . Is that what your suggesting is 27 ma? As in the direct reading in the instructions attached at no10. I only got 7.88 ma when probe set at plate current and meter set at ma.