# How to measure Amp?

Could somebody explain in a very easy way (with a drawing of what goes to what) show how one measures how many amp a motor is taking?

Thanks!

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Run it off a 2000ma battery. Use some of that hot melt glue you like so much and glue the shaft so it will just barely turn. Now hook it up to the battery and start a stopwatch. Now if it doesn't blow up, just wait for the battery to die and check the stop watch. Now simply devided 2000 by the time gone by and there you have amp-hours which can simply be converted to amps!

It is a 4.000 Amp motor!

I did this:

Turn the knob to the other 2000 (6 clicks left of "off". This is 2000 ohms (Or 2K.). Put the red lead in the leftmost socket. Attach the end of the red lead to one pole of the motor. Attach the black lead to the other pole of the motor. Write it down (call it "R").

Write down your battery voltage. (Call it "V".)

Get a calculator. Perform the operation V / R. (V and R are the numbers you wrote down above.)

The result is your stall current in Amps. (Stall current is when you have put such a heavy load on the motor that it can't turn and it starts to gethot and very soon the blue smoke will come out.)

V: 7,2
R: 0,0018

7,2 / 0,0018 = 4.000

Should I assume that is Microamps or something, so it is actually 4,0 Amps?

Happily, you have translated the Kohms into ohms before doig the division. 7.2/0.0018 is actually 4000 amps.

No wait a minute. You use "." as a thousands separator and "," as a adecimal point, don't you? I'm confused.

Is your battery seven point two volts and your resistance zero point zero zero one eight ohms?

Assuming your resistance measurement is correct, this does appear to be a 4A stall motor. Now, this information isn't all that relevant. The motor might only draw 1A when it's running normally. (Not stalled.)

Cheers :)
Do solution 1 but don't try to stall the motor.