A multimeter or a multitester, also known as a VOM (volt-ohm meter or volt-ohm-milliammeter), is an electronic measuring instrumentthat combines several measurement functions in one unit. A typical multimeter can measure voltage, current, and resistance . A multimeter can be a hand-held device useful for basic fault finding and field service work, or a bench instrument which can measure to a very high degree of accuracy. They can be used to troubleshoot electrical problems in a wide array of industrial and household devices such as electronic equipment, motor controls, domestic appliances, power supplies, and wiring systems.