# Measuring resistance

I would like to measure the resistance of a resistor in the most basic way by running a current through it and measuring current and voltage. I understand that I have basically two options to place voltmeter and ammeter: 1. If I measure the voltage over the ammeter+resistor, I get an error due to the non-zero resistance/voltage drop over the ammeter. So basically the voltage I measure is not the voltage over the resistor but somewhat larger. The measured current is correct though. This method should work well if the measured resistor has a much larger resistance than the ammeter.
2. If I measure the voltage over the resistor, the measured voltage will be correct, however now the measured current will be larger than the current through the resistor. I understand that if the resistor has a much smaller resistance than the voltmeter this error should be negligible. This method should work well for measuring small resistances.

I have two questions:

1. If the resistor to be measured has a resistance value that lies in-between those of voltmeter and ammeter, how do I decide which method to use?
2. If a series resistor (of known resistance) is used, how would I set up volt/ammeter?

Please keep the answer simple as I am not an electrical engineer.

• You can try both methods and see what difference there is. Likely, there is none. If there is, though, either your apparatus has awful internal resistance, or the resistance it very close to theirs (either to that of the Ameter, or Vmeter). May 4 '18 at 7:24