On Wed, 16 Oct 2019 at 06:10, bryburns via Groups.Io <bryburns=
[email protected]> wrote:
On Tue, Oct 15, 2019 at 03:42 PM, Rune Broberg wrote:.
In the case of my BNC short, I don't think I have the ability to reliably
measure a resistance that small. The ohmmeter I have won't go lower than
0.05 ohms even when shorting the test leads together. When measuring the
short I used, it still measures 0.05 ohms. I doubt that many folks doing
hobbyist work can measure the resistance of their short either. uant to
look into this. I am sure it is reproducible.
--
Bryan, WA5VAH
An interesting post Bryan.
I agree that the resistance of the short is unlikely to be an issue, but
the resistance will increase with frequency due to the skin effect.
To measure low resistance values one needs to use 4-wire Kelvin connectors.
But even without a meter with that facility, it is very easy to use a
constant current source and a decent handheld multimeter. Many cheap
handheld multimeters can read 100 uV easily. Pass 100 mA thru the DUT and
you a 1 milli ohm resolution.
Dave.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...
Telephone 01621-680100./ +44 1621 680100
Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom
