Three Practical Tips for Using a Multimeter
1. Testing Continuity of Wires with a Multimeter
First, confirm there is no voltage across both ends of the wire. Either DC or AC voltage may damage the multimeter. Then use the resistance range of the multimeter to measure the wire resistance. Some multimeters have a continuity test range for directly checking whether the wire is conductive.
Use the continuity range or the lowest ohm range of the multimeter. Measure both ends of the conductor. If you hear a "beep" sound or the analog meter needle points to zero, the wire is conductive. Otherwise, it is open-circuited. For long wires, take one wire as the common line and measure all other wires against it.
If the multimeter is equipped with a buzzer, use the buzzer range; if not, use the resistance range. A buzzer sound or infinite resistance indicates the wire is conductive, and no buzzer sound means the wire is broken.
2. Checking Wire Continuity with a Multimeter
Tie one end of two conductors together for measurement. A reading of zero indicates a continuous path, while a measurable resistance value indicates a short circuit. To test the insulation performance of the two conductors, separate the conductors at the other end. A resistance reading means good insulation performance (the resistance value depends on insulation material, cable length, ambient temperature and cable temperature). Zero resistance means the cable is shorted or grounded.
3. Testing Circuit Continuity with a Multimeter
Insert the red and black test leads into the resistance jack and COM jack respectively. Turn on the multimeter and switch to the minimum resistance range. Touch the tips of the two test leads together to verify the meter works properly; a reading of zero or a value near zero is normal. Then touch the probe tips to both ends of the circuit under test. A reading of zero or near zero indicates a continuous circuit. If resistors or other electrical components are connected in series in the circuit, switch to a higher resistance range for measurement. Readings vary according to the series resistance value. Always cut off the power supply of the circuit before measurement.
