How to Measure Amps With a Digital Multimeter

By Jonra Springs

A digital multimeter measures the amount of current used by an electrical device or component. Most multimeters include a settings option for measuring current in amps. Replacement electrical parts and components must have matching amperage ratings to work correctly so proper testing with a multimeter is an essential step before carrying out repairs or modifications.

Step 1

Turn on the digital multimeter. Most digital systems run a self-check before they are ready for use. Allow a minute for the meter to complete its testing.

Step 2

Set the function selector to read amps from battery power or alternating current. The function setting "A~" measures alternating current in amps, or AAC; "A=" measures direct current in amps, or ADC.

Step 3

Set the range so the maximum is well above the highest reading expected. This will protect the meter from getting overloaded. If you overshoot the range and cannot get a reading, set it lower.

Step 4

Connect the leads to the proper terminals for measuring current. Connect the black lead to the "COM," or common terminal. Connect the red lead to a terminal marked for low- or high-current measuring. The low-reading terminal may be identified as "300mA." This would give readings in milliamps; 1 milliamp equals .001 amps. Multiply by 1,000 to get the figure in amps.

Step 5

Break into the circuit to measure its current. Set the red probe on one open end and the black probe on the other. This may require cutting a wire to get the probes between the circulating current. The idea is to let the current flow through the digital multimeter to allow it to get a reading.