How to Calibrate an Ammeter

By Samuel Markings

Electronics is the study of electrical circuits, which generally consist of power sources, wires and other integrated electrical components. A number of diagnostic tools are important in the commissioning or testing of electrical circuits. These tools include devices such as a voltmeter, ammeter or combined multimeter. These devices are usually calibrated by the manufacturer before they are shipped, but you may need to calibrate some of the cheaper varieties yourself.

Things You'll Need

  • Precision voltage source
  • 1 kOhm shunt resistor
  • Ammeter
  • Wire

Step 1

Connect the two terminals of the voltage source to either side of the 1 kOhm resistor.

Step 2

Connect the two terminals of the ammeter across the resistor, or in parallel. This will allow the current flowing the resistor to be determined.

Step 3

Switch on the voltage supply, and set it to 1 V.

Step 4

Calculate the expected value of current using Ohm's law. Ohm's law states V=IR, where V is the voltage, I is the current and R is the resistance. In this case, the expected current is I=V/R and is equal to 1 milliamp, or mA. Compare this with the measured value shown on the ammeter. If the values are different, adjust the calibration knob on the ammeter to match 1mA.

Tips & Warnings

  • To ensure the ammeter is calibrated over a wide range of currents, carry out the procedure with resistors of different value.