[volt-nuts] nA advice

[Andrea Baldoni]

On Fri, Nov 13, 2015 at 01:56:19PM -0500, Charles Steinmetz wrote:

> Rob wrote:
> 
> >50V across 5GOhm is 10nA. Put a standard multimeter's 10MOhm input in
> >series and
> >you have 10mV per nA reading. Anything below 100mV is pass.

Yes, Rob. I late also thought about it that way while answering to Todd.
In effect I wasn't used to think to DMM the way it was for galvanometers :)

> Also, quite a few of the Fluke portable and handheld DMMs from the last 35
> years or so (including the faithful old 8050A and the "80-series" DMMs)
> measure conductance (1/R) with a resolution down to 0.01nS (= 100G ohm).
> There are lots of them with this capability on the used market for $10 and
> up, and several are still available new (but not for less than Eu100, to my
> knowledge).

Charles, I own two new generation fluke portables (one is a 177 and the
other is the cheap 15B) and no one has this characteristic anymore, who knows
why, but it's very interesting. According to

http://www.fluke.com/fluke/uses/comunidad/fluke-news-plus/articlecategories/rd/the%20mho%20that%20become%20siemens

the new multimeters with conductance measure are 87V and 189. No one fits the
100 EUR range by far, but I can buy an used 80-series one, they are very
cheap and I can bring them on the field while I would like to let the 34401A
in the lab. I saw the 8060A resultion is only 0.1nS; I cannot find the specs of
the 8050A (neither the user's manual). Which one do you suggest?

Best regards,
Andrea Baldoni