nzkunal
Member level 2
measure low resistance
Hi,
I need to design a very accurate ohmeter for a copper wire tube. At present I put 0.5A through the wire (26.4-28.4 ohms). The voltage is then shifted down throrough a potential divider. The tester seems to drift with time. I am currently running some tests to monitor the affect of the current on resistance. The reason I am using the high current is so I can get a higher resolution on my ADC. I believe this is more accurate than putting less current through and then amplifying it later in the circuit lower SNR etc.
Does anyone know of any techniques using bridges etc to measure low resistance values (round 20-30 ohms) with an accuracy of round +/-0.05 ohms?
Thanks in advance
Hi,
I need to design a very accurate ohmeter for a copper wire tube. At present I put 0.5A through the wire (26.4-28.4 ohms). The voltage is then shifted down throrough a potential divider. The tester seems to drift with time. I am currently running some tests to monitor the affect of the current on resistance. The reason I am using the high current is so I can get a higher resolution on my ADC. I believe this is more accurate than putting less current through and then amplifying it later in the circuit lower SNR etc.
Does anyone know of any techniques using bridges etc to measure low resistance values (round 20-30 ohms) with an accuracy of round +/-0.05 ohms?
Thanks in advance