[volt-nuts] easy 3458A AC calibration
Electronics and Books
electronicsandbooks at yahoo.com
Wed May 20 15:46:44 EDT 2015
It is stated that the ac calibration of a 3458 is so difficult. at least the equipment mentioned is so difficult to obtain. but look what you need. a hp signal generator 3325 where i have a pile of (any other good generator will do to), an other hp 3458 and 3 different thermocouples. very expensive nowhere to be found and very delicate. hp not procduced them for 40 years or ballantine which cost more then the meter your calibrating.
but now for the accuracy. the signal generator has only 3 digits of amplitude resolution. if you see the accuracy in the hp protocol what to measure it is not possible to generate that.
and for the thermocouples. they give only millivolts. you need an other 3458 with no offset or better a nanovolt meter to measure them.
a far easier solution is a hp powersensor 8482a on a hp power meter. it is a thermocouple of the correct frequency range and can be measured accurate enough for the generator.
the ac calibation is not an exact value as the volt or resistor but only a deviation in the frequency range. it is even difficult to obtain the deviation in 3 digits.
ok it took me an hour but then i was done.
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