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# Is it possible to change the FSD of an analogue panel meter?

I have a 1940s panel meter from an old radio but it only has a FSD of 1.5mA. I am intending to use it as an ammeter so I don't think it's possible to put a resistor in series. Any help would be greatly appreciated.

## Discussions

Best Answer 10 years ago

You don't put the resistor in SERIES, you SHUNT it, or put it in parallel. What FSD are you trying to achieve ? Steve

Answer 10 years ago

Hi, thanks for the response, i'm not entirely sure what FSD i'm trying to acheive but if you could tell me the method for calculating required values of resistors, etc, that would be greatly appreciated. I am unsure of the internal resistance of the panel meter as it came with no information but I should be able to calculate it quite easily. Thanks again for the reply.

Answer 10 years ago

If you want to measure say 1Amp FSD on your 1.5mA FSD meter, then your shunt must have a resistance 1.5/1000 x less than the meter.

Answer 10 years ago

oh ok, thanks very much... that's great :D

Answer 10 years ago

PS You need to know the internal resistance of the meter.