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Topic: Measuring microamps (Read 2 times) previous topic - next topic

Grumpy_Mike

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Would a linear analog Hall sensor be able to pick up on the moving charge field?


No way too small by many orders of magnitude.

polymorph

This should not be too difficult. A 1k ohm resistor at 1mA will only drop out 1V, which is about the resistance of an analog meter.

So you could do this with a 1k from ground to the Ge transistor emitter and an analog input pin, and the collector of the transistor to 9V.

If you want or need better resolution, you could put an Op Amp in there to multiply the voltage x4, so at 1250uA there'd be 5V into the Arduino.
Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

Grumpy_Mike

Quote
which is about the resistance of an analog meter.

What sort or rubbish meters have you been using? Most analogue meters I have used have had 100K input impedance.

By the way have you seen my transistor testing project:-
http://www.thebox.myzen.co.uk/Hardware/Transistor_Tester.html

polymorph

"What sort or rubbish meters have you been using? Most analogue meters I have used have had 100K input impedance."

What sort of rubbish -current- meters have you been using? In context, I was talking about the current meter in the circuit referred to in the first post. Most analog -current- meters I've used have had around 1k (not K) input impedance.

Nice little transistor tester.
Steve Greenfield AE7HD
CET Consumer Electronics and Computer
Please don't read your attitudes into my messages

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