[volt-nuts] hp3457a low voltage range behavior
frank.stellmach at freenet.de
Tue Sep 3 17:21:13 EDT 2013
The more important parameter is Ibias, the input current, vs. the input
Neither Input Resistance, nor input bias current, nor input capacitance
are specified for the 3457A.
Input current is on the order of a few pA, up to 20pA, and input
capacitance, I would guess, several dozen pF, or you'll have to study
the CLIP, if there's a bigger cap in the front end.
Even this would be 100nF, you can calculate, that the input will charge
quickly with open input jacks, and then will actuate the 100:1 divider
by relais, if 3V were exceeded. The 10MOhm then will quickly discharge
the input cap again.
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