-------- In message <CANX10hA5BeZYCXJORQ5r4h=cbbv2jpzedswkfswg0hu6hnp...@mail.gmail.com>, "Dr. David Kirkby (Kirkby Microwave Lt d)" writes:
>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. The dominant factor in the resistance you want to measure is the pressure on the contacting surfaces. If the contact pressure is high enough, making the joint "gas tight", you can treat it as one contiguous piece of aluminium and just do the math (= differential equations for complex geometries) If the contact pressure is too low, trying to measure the joint resistance is a fools errand, because it will not be stable over any parameter (voltage, current, humidity, vibration, air composition, ...) The only known way to measure ohmic resistance in the micro-ohm domain with any precision is caloriometric methods, and they are experimentally troublesome to no end. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
