I am using a 100W, 2 ohm power resistor (old wound cement unit) in a circuit to do some basic measurements with. When cold, the resistor measures 2.1 ohms on both of my DMMs.
After use, when the resistor is hot, I attempted to measure the resistance, but I ended up with some crazy results, which, depending on which way I connect the leads, tell me it is either between 3 to 4 ohm, or 0 to 1 ohm.
Since the lead placement affected the reading, I assumed that somehow this resistor was generating a voltage when hot, but I can detect no voltage with any of my meters.
What is going on here, and why in the heck is lead placement affecting the results? Additionally, how can I accurately measure the resistance of this hot resistor?
Thanks for any insight into this,
Jon