Hi. I believe that for a microammeter to read correctly in a circuit that has been designed with a microammeter with a particular internal resistance, a replacement microammeter of the same FSD must have the same value of internal resistance to show the correct current. Where a replacement microammeter has an internal resistance lower than the original, you can of course simply add a sereis resistor to bring up the resistance to match the original. However, if you have a meter with a larger internal resistance it's not possible to use resistors that will enable the replacement meter to read correctly as the original.
What I think I need then is a circuit which will allow any microammeter to read the same as the original, no matter what it's internal resistance.
My original 100 uA meter has an internal resistance of 260R. I can buy a replacement 100 uA meter that has an internal resitance of 800R. But, I need a circuit to enable me to use it so it reads the same as the original meter in the circuit designed for the original meter. Meter is DC meter.
There may be a circuit out there on the WWW. But, I'm not sure what to put as a search string.
What I think I need then is a circuit which will allow any microammeter to read the same as the original, no matter what it's internal resistance.
My original 100 uA meter has an internal resistance of 260R. I can buy a replacement 100 uA meter that has an internal resitance of 800R. But, I need a circuit to enable me to use it so it reads the same as the original meter in the circuit designed for the original meter. Meter is DC meter.
There may be a circuit out there on the WWW. But, I'm not sure what to put as a search string.
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