04-05-2012, 06:34 AM
I seem to have sorted this out. I changed the rectifier for a BY133 and hundred ohm resistor and reset the calibration.
I'm curious about a couple of points though. The Heathkit instructions say that for DC tests the positive probe should be connected with a screened cable and have a one meg resistor at the prod end. What I'm curious about is why, if these things are needed for DC, aren't they necessary for AC? Also, given that AC and DC use different sockets on the meter, couldn't the resistor be in that? It certainly seems to work fine with normal test leads so perhaps these extras aren't needed on this Cossor one.
Cheers
Joe
I'm curious about a couple of points though. The Heathkit instructions say that for DC tests the positive probe should be connected with a screened cable and have a one meg resistor at the prod end. What I'm curious about is why, if these things are needed for DC, aren't they necessary for AC? Also, given that AC and DC use different sockets on the meter, couldn't the resistor be in that? It certainly seems to work fine with normal test leads so perhaps these extras aren't needed on this Cossor one.
Cheers
Joe
