Re: [volt-nuts] Best way to measure micro Ohms

I use a Keithley 2182 and 6221 nano-ohm setup at work. It is a combination of a reversing precision current source and a nanovoltmeter with embedded software to manage the process. I can reliably measure into the 50 nano-ohm regime.The surface chemistry of the metal joint is very important.

Re: [volt-nuts] Best way to measure micro Ohms

A DMM with good low resistance capability will have an "offset compensated ohms" feature. A large current is used and then a small current is used. The slope of the line formed by V-I points is the true resistance. Measuring tiny DC voltages is easier than measuring tiny AC voltages. More

Re: [volt-nuts] Best way to measure micro Ohms

On 17 September 2017 at 21:58, Mitch Van Ochten < mi...@vincentelectronics.com> wrote: > The Keithley 2002 uses DC but automatically takes a reading of any offset > voltage and subtracts it (offset compensation). Rated accuracy on the 20 > ohm range (2 years) is +/- 26 ppm, and with 10 averages

Re: [volt-nuts] Best way to measure micro Ohms

On 17 September 2017 at 20:12, wrote: > The question is what accuracy you need. > No a lot. I just want to find out if there's any voltage drops that are significantly higher than I would expect. The unit makes an RF transmission line, and the loss at RF is significantly higher

Re: [volt-nuts] Best way to measure micro Ohms

The Keithley 2002 uses DC but automatically takes a reading of any offset voltage and subtracts it (offset compensation). Rated accuracy on the 20 ohm range (2 years) is +/- 26 ppm, and with 10 averages it has a resolution of 0.1 microohms. Best regards, mitch -Original Message-

Re: [volt-nuts] Best way to measure micro Ohms

The question is what accuracy you need. The classical way to do that (achieving high accuracy) is to apply a known accurate current (say 10A) and measure the voltage drop accross the rod with a nanovoltmeter. As the piece of aluminum is isothermal you should not expect a big thermovoltage. You

Re: [volt-nuts] Best way to measure micro Ohms

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[volt-nuts] Best way to measure micro Ohms

I want to measure the resistance between two bits of aluminum. Each are 40 x 30 mm across. One is 250 mm long, the other is 8 mm long. I'm wondering is surface oxides are on the faces, so despite being held together with bolts, the resistance is perhaps not as long as I would expect. There's also