Wire Resistance

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Wire Resistance

Post by Sam » Sun Apr 24, 2011 2:29 pm

I built a relatively crude shunt fixture consisting of two 49.9 ohm resistors (one leading from the input and one leading to the output), both connected to a grounded 10 ohm resistor. The DUT connects to the common connection of the resistors. This is a 16.7 ohm shunt fixture that is optimal for measuring small resistances.

I did Reference calibration, using a 100 ohm resistor as the reference, and measured the resistance of a short piece of #30 wire. The resistance was extremely small--0.012 ohms at 1 MHz and 0.043 ohms at 25 MHz. Yet all indications are that they were accurately measured within a couple of milli-ohms.

I posted a photo of the scan and some explanatory comments:

Measuring resistance with a shunt fixture is very similar in concept to 4-wire Kelvin measurement of DC resistance.

Sam W.

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