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I tried to measure the resistance of my electrolysis setup (rusty object on cathode, clean iron anode, electrolyte = 3l H2O + 1tb spoon baking soda). But the resistance fluctuated from 50 to 70 kΩ even when everything was still. During the reading it would usually climb up. Sometimes I even got a negative reading (when I added more baking soda). Could something about the way the multimeter measures resistance cause this? How can I measure the actual resistance and in what range should I expect it to be?

I want to know because I have a 12 V, max 12 A power supply + (16 A current limiting socket) and I worry that it is just too much power for some of the cables.

Note: The power supply is a 350 W ATX power supply with a selection of voltages from 3.3 V to 12 V.

winny
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Adam Labuš
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  • I'm not a chemist, but if there is some activation potential which your DMM in resistance mode does not reach over, you will get different results with multimeter versus 12 V applied. How about setting it for current measurement and hook it in series with your power supply? – winny May 04 '23 at 11:15
  • Gonna have to buy a better ampmeter then, mine is rated at max 10A. – Adam Labuš May 04 '23 at 12:47
  • You can also cheat with a shunt resistor of suitable value and measure the voltage across it. – winny May 04 '23 at 12:52

1 Answers1

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The electrolyte cathode and anode form an electrolytic cell. The voltages produced will influence the ohmmeter. The meter injects a current then measuring a voltage that calculates the resistance.

To measure the resistance, measure the voltage and current while operating. Apply Ohm’s Law.

The resistance is dependent on the evolution of the gases produced.

RussellH
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