I would like to interpret my ammeter. I don't understand what the point with the numbers 2,20,200 means and what is the exact current I am measuring. Thanks
Best Answer
You've carefully trimmed the photos so we can't see where your probes are connected.
When using the 2m, 20m, and 200m ranges (switch positions) the red meter lead should be in the "Volts/Ohms/mA" socket, and the black lead in the "Com" socket. For the 20A range, the red lead should be in the "20A" socket.
I suspect you are using the "20A" socket for all readings. If so, the readings on the mA ranges will be meaningless.
If so, the correct current is read with the range switch in the "20 A" position, and the current is 0.05 Amp, or 50 mA.
If the full scale value of the ammeter is 5mA, calculate the proper value of resistor in which 5mA will flow when 5 volt is connected across the resistor. By ohms law, this will yield 1000 ohms.
Connect the resistor in series to the ammeter. Now the ammeter which converted to a voltmeter should have the full scale read out when 5 volt is connect to it.
This approach assumes the ammeter has zero internal resistance. In reality all ammeters will have some resistance. Because of this, the calculated value of the 1000 ohms series resistance must be tweaked to a finer value by introducing another small series resistance or another large parallel resistance.
Best Answer
You've carefully trimmed the photos so we can't see where your probes are connected.
When using the 2m, 20m, and 200m ranges (switch positions) the red meter lead should be in the "Volts/Ohms/mA" socket, and the black lead in the "Com" socket. For the 20A range, the red lead should be in the "20A" socket.
I suspect you are using the "20A" socket for all readings. If so, the readings on the mA ranges will be meaningless.
If so, the correct current is read with the range switch in the "20 A" position, and the current is 0.05 Amp, or 50 mA.