Measuring Large resistances

Hmm.. I think you're right on that point. I do have one that does, but probably most do not. Benchtop instruments like my Agilent 34401A meters do have an "infinite impedance" setting.

Carbon? AFAIK something like Ruthenium oxide is more common in chip resistors. Ohmcraft makes their using a kind of printing method which is automated, so it should be consistent. Here is a white paper on their process:

Fluke 87-5, for example. DC voltage accuracy is 0.05% + 1 count on the

But only 1% in the 60nS range (infinity to 16.667M ohm), unfortunately. A 100M resistor would have a conductivity of 10.00nS so the resolution is pretty much there, but not the accuracy.

Probably lots of other 4-1/2 digit handheld meters too.

Hi guys Thanks for all the enlightening on the subject. The model of the meter I use at the Lab is the Agilent 34401A which Spehro incidently mentions has an infinite resistence setting. I couldn't find that ... which means I'll have to browse through the thick manual. It doesn't seem to deliver more then then a 10V output though. I suspect it might be measuring the limitations in its accuracy readings or the thermal noise in the resistors.

Kreyen

Thanks.

Oh drear, it has a 10M ohm input when measuring voltage; measuring resistance is entirely different.

The measurement problems may be exactly that, measurement method. For