[sci.electronics] current measurement

thoad@athena.mit.edu (Thomas A. Digiacomo) (02/24/90)

Can anyone help me with the name of a current measuring system and its maker
which I can use to measure ripple currents of LESS than 10 micro-amps.
I am trying to construct a system to make conducted (and later radiated) EMI
measurements on power supplies, and am limited by the following:

	1) ripples of 10 micro-amps (or less) must be detectable
	2) the DC currents of up to, say, 20 amps, must be ignored
	   (which may cause probe transformer core saturation)
	3) non-invasive probing, preferably clip-on
	4) little or very well-defined loading by the probe on the
	   device under test

I'm trying to avoid building a current transformer myself, because I'd rather
have a well-specified unit.  There should be something out there to do this
because FCC regulations force manufacturers to pass certain regulations on 
conducted and radiated energy.  Any information on the current probe or the 
construction of a test set-up to do this that could be sent thru net mail would
be appreciated.  

Thank you.


Tom DiGiacomo
thoad@athena.mit.edu