- A volt-ohm meter is also known as a mulitester or multimeter. It is a device that measures electricity. Depending on the meter, it might measure the current, voltage or resistance. The instrument typically includes two leads attached to probes. The red lead is the positive terminal and the black lead is the negative or ground terminal. Some meters are handheld devices used in the field, and others are highly accurate bench instruments.
- A volt-ohm meter is used to troubleshoot electrical problems or verify electrical currents and voltage use by connecting its test probe to the item being tested. It can be used to test batteries, motor controls power supplies, wiring systems and appliances. The test probes can be retractable hook clips, crocodile clips or a pointed probe.
- There are two basic types of volt-ohm meters: analog and digital. Both measure DC and AC voltage, resistance and DC current. A digital meter presents information in a digital format; an analog readings are presented by a pointer. Prices for volt-ohm meters range from under $20 to thousands of dollars.
- When using a meter, the term "volts" refers to the force behind the electricity. "Amps" is the quantity of electrical flow per minute, and "ohms" refers to the resistance of the wire to the electricity's flow. When the ohms range is zero, it indicates there is an easy flow of energy, whereas an infinity reading implies the electricity is being blocked.
- The multimeter evolved from the radio receivers of the 1920s. As the years progressed, electrical systems became more complex. Vacuum tube electronic devices---instruments used to switch, amplify, change or create an electrical signal by manipulating electron movements in a low-pressure space---became common. To meet these new demands, the multimeter also became more complex. A modern device might test several parameters to confirm a network cable's performance.
