How to Use a Digital Multimeter

A digital multimeter is a device used to measure various properties of electricity, from voltage and current to capacitance frequency. In fact, many people may never use a digital multimeter for every capacity that it offers. The multimeter combines these abilities to provide an an efficient method for measuring these properties using just one device. Electricians are most likely to use a digital multimeter, but anyone might use one for such purposes as testing batteries thought to be dead or to make sure electrical current has been shut off.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Multimeter

Testing With a Multimeter

1. Set the multimeter dial to ACV if testing for AC voltage or DCV if testing for DC voltage. Set the range to a number higher than you expect the actual reading to be; if you don't have any idea what the reading will be, then just set it to the highest number. Plug the test leads into the port panel and apply them to the circuit for AC voltage, adjusting them until the measurement is displayed on the LCD readout. To test DC voltage, connect the test lead colored black to the ground lead, or negative polarity point, and take the reading.

2. Set the dial for either AC or DC to test for current and then set the range. If testing with a clamp meter, open it and close the head upon a single conductor, making sure it has closed totally around the conductor before releasing the level and taking the measurement. When measuring current on an open line, plug the leads in and set the dial to either AC or DC, apply the leads and take reading.

3. Set the dial on the digital multimeter to capacitance and plug in the leads. When the capacitor discharges, connect the leads to the capacitor terminals and take reading. The measurement should be the same as the rating listed on the capacitor and any variation indicates a need for replacement of the capacitor.

4. Set the dial to Hz to test for frequency. Hz stands for hertz, which is the figure used to determine the number of times a wave form is repeated. Plug the leads in and connect to the circuit, comparing the measurement with the frequency listed on the component being tested.

5. Turn the power off that goes to the component being tested before testing for resistance. Set the digital multimeter's dial to resistance mode and again select the range. Plug the test leads and take reading, making sure that the contact is not corrupted in any way; you must have a clean contact between the leads and the component, otherwise you may get a much higher reading than is authentic.

Tips & Warnings

• Make sure to keep fingers behind the guards on the test probes while conducting measurements.
• Don't use the multimeter if appears to be damaged or if the leads are damaged. Using the meter on circuits in excess of 4,800 watts can serious injury.