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How to Test Instruments with Digital Multimeters

Electricity is created by the flow of charged particles known as electrons. The measurement of key quantities in electrical instruments is an important means of fault-testing. A digital multimeter is a battery-powered portable device that measures quantities such as voltage, current, continuity and resistance. It consists of a main unit, with a number of buttons, and an LCD screen. Two probes with metal tips are plugged into the main unit, then they are brought into contact with the measured device.

Instructions

- 1
  Plug the two measurement probes -- one red, the other black -- into the main unit of the multimeter. Plug the red probe into the positive terminal, and the black probe into the negative terminal.
- 2
  Select the measurement function by rotating the dial on the front of the multimeter. The choices are AC voltage, DC voltage, AC current, DC current, resistance and continuity. The DC voltage setting has an additional series of sub-settings for selecting the measurement range, in volts or millivolts. Select a range that is appropriate for the measurement by rotating the dial on the front of the multimeter. If you don't know the measurement range, use the higher setting.
- 3
  Perform the measurement. Bring the measurement probes into contact with the component or instrument that is being measured. The LCD screen will indicate the measured value. If the continuity function is being used, you will hear an audible beep if positive electrical continuity is found.

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