How to use a multimeter

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A multimeter can be an intimidating piece of a equipment to the uninitiated. But it’s not as difficult to use as it looks – here’s some simple steps to follow for most common situations.

How to measure AC voltage (e.g. 240VAC, 24VAC)

1. Select the AC voltage option, and if the multimeter supports it, the voltage range. For example, if you’re measuring 240VAC, select the lowest option higher than 240 in the AC voltage section.
2. Ensure the red probe is plugged into the ‘V/Ohms/mA’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure the voltage between two conductors by touching a probe on each.

How to measure DC voltage (e.g. 12VDC, 24VDC)

1. Select the DC voltage option, and if the multimeter supports it, the voltage range. For example, if you’re measuring 24VDC, select the lowest option higher than 24 in the DC voltage section.
2. Ensure the red probe is plugged into the ‘V/Ohms/mA’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure the voltage between two conductors by touching a probe on each.

How to measure current (in amps)

1. Select the ’10A’ or ‘A’ option in the current section.
2. IMPORTANT: Ensure the red probe is plugged into the ’10A’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure the current by running the electricity through the multimeter (in series with the electrical circuit).

How to measure current (in milliamps or less)

1. Select the mA current option, and if the multimeter supports it, the current range. For example, if you’re expecting the current to be a maximum of 100mA, select the ‘200’ or ‘200m’ option in the current section.
2. Ensure the red probe is plugged into the ‘V/Ohms/mA’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure the current by running the electricity through the multimeter (in series with the electrical circuit).

How to test continuity (conductivity)

1. Select the continuity or diode test option.
2. Ensure the red probe is plugged into the ‘V/Ohms/mA’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure continuity between two conductors by touching a probe on each. Most multimeters will provide an audible signal indicating continuity; alternatively the display may just indicate a value close to zero.

How to measure resistance

1. Select the resistance (Ohms) option, and if the multimeter supports it, the expected resistance range. For example, if you’re expecting the resistance to be a maximum of 150 Ohms, select the ‘200’ option in the resistance section.
2. Ensure the red probe is plugged into the ‘V/Ohms/mA’ socket. The black probe should be plugged into the ‘COM’ socket.
3. Measure resistance between two conductors by touching a probe on each.

 

Obviously a multimeter must be used with care and common sense: we don’t take any responsibility for injury or damage caused by the incorrect use of electrical equipment.