At 09:26 PM 9/10/2004 +1200, you wrote:
>Any circuit suggestions for a multimeter plug-in that could measure
>1nA (hopeful) to a few uA ? I was thinking perhaps A -> V and
>use the low DC volts range
>
>I've got a couple of multimeters - one goes down to 20uA and the
>other to 2000uA. Measuring a sleeping 12F675 gets you 00.0uA
>or 0.000mA (yes, it is alive, I can wake it up to do stuff). Helpful
>in the sense that it shows the battery will last a flipping long time,
>but there's nothing there to hang your hat on
>
>Googled and Googling around a bit but not too fruitful yet. Maybe
>I'm not searching for the right thing, and there's such a bewildering
>array of parts and technologies I might not even recognise what I
>need when I see it anyway
>
>The old NatSemi Linear Apps book has a 200pA-100uA circuit
>(LB37) for the LM216A and a 100uA  moving coil meter, but the
>LM216A seems to have dropped off the radar. I'm certain there
>will be an equivalent or better around, but short of downloading
>squillions of op amp datasheets...........
>
>TIA

You may be able to use a cheap DVM on a voltage range with
an external resistor (check the specifications). My HP 5-1/2 digit
meter can be switched to >10G ohm on low volts, so it's easy to measure
nA level leakages.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com




_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist