You need to put your 190 volts inside a regulated loop to get the effective
source impedance way down.
?
Or, you could set it to some lower voltage like 150.xx so that when the
calibration takes place, the correct input is seen.
?
?
Tom
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----- Original Message -----
Sent: Saturday, December 29, 2012 9:38
PM
Subject: [TekScopes] 2465B DMM cal
?
So I finally found a transformer that will give me the 500 Volts I need
to calibrate the DMM on the 2465BDM scope. The part that I'm having
problems with is the fact that it appears to change the impedance of the
test leads when it goes in to actual testing. For example I may set to
190.00 volts AC and then when it goes in to cal "busy" mode it jumps to
220+ volts. I can only assuming it's doing something to change the
impedance of the leads. It passes on to the next test however the
calibration is way off when I finally get to use it. Has anyone had
any experience with this type of calibration. I have the scopes DMM in
parallel with a reasonably calibrated DMM to act as a transfer
standard. I'm making the assumption that the scopes DMM will not
change it's input impedance..clearly
falsely.
Thanks,
Jeff
