funny but also not so funny - how to measure high value resistors (gigaohm)

I spilled my box with high value resistors.

well.

the problem is the 1G and 3G resistor look absolutely the same ?


what to do ?

nicholas

bust out the dmm

pucho812 said:

bust out the dmm

Click to expand...

right thats the funny part !



the less funny part 30 giga ohm resistor are not cheap

Measure with known parallel resistor?

this guy has a solution for my problem: Charles Wheatstone

die altbekannte Wheatstonesche Messbrücke...

Ah yes, Lost treasure (at least for me) http://en.wikipedia.org/wiki/Wheatstone_bridge

If you need to measure Gigaohms resistors, go the Charles Wheatstone route.

But if all you need is to sort the 1G from the 3G, you can do it a much simpler way with a decent DMM.
Say your DMM has a 20 Meg input impedance. Those 20M will make a voltage divider with the unknown resistor.
Connect this resistor to a 48V source for instance, and measure the voltage between ground and the resistor. About 0.9V it's the 1Gig. 0.3V it's the 3Gig.

Axel

thanks Axel


that makes sense. I'm going to do that. Nicholas