That should be 1mA external current.I see from your first post that 1.51V produced full scale on the meter. Measure the voltage across the meter terminals when it is a full scale. Use the 158.8 ohms from the movement and calculate a resistor value that will give the meter voltage with 10ma external current. Place that resistor in parallel with the meter.
Fingers got going to fast. Yes, 1ma. As you see, I also did a total re-think about the whole thing. Pretty sure either way would work.That should be 1mA external current.
I agree and that was my next thought as well. Thanks again guys for the help.........It might be better to find the value of the shunt empirically using a variable resistor as a shunt, initially set to zero ohms and then adjusted to obtain FSD with 1mA. A fixed resistor could then be substituted.
Timescope
No. The diodes are there to protect the moving coil meter from excessive currents.Do you want to measure ac or dc current? The diodes are there to allow measurement of AC but if you don't need that then you would be better off removing them.
From post #4.I took the meter apart and there is a diode bridge network (I am assuming it is there because this is a DC ammeter)