multimeeter

A multimeter is a handheld electrical measuring instrument that combines several measurement functions in one device. It is used to test and troubleshoot electrical and electronic circuits by measuring quantities such as voltage, current, and resistance, and in many models also capacitance, frequency, temperature, and diode behavior.

There are two main families: analog multimeters, which use a moving-coil meter and require interpretation of a scale, and digital multimeters (DMMs), which display readings as numeric values on an LCD. Digital models are more common today due to higher accuracy and ease of use.

Common measurements include DC voltage, AC voltage, DC current, AC current, and resistance. Many multimeters include a continuity checker that emits an audible beep when a near-zero resistance path is detected, as well as diode-test functionality. Some models also offer capacitance, frequency, and temperature measurements.

A typical handheld meter has a rotary selector, a set of input jacks (usually a common COM jack and one or more voltage/resistance/mA or 10 A current jacks), a display, and input protection fuses or circuit breakers. Modern units often feature auto-ranging, which eliminates manual range selection.

Safety and usage guidelines are important. Users should observe proper precautions, select the correct range or enable auto-ranging, and avoid measuring high voltages or currents without appropriate protection. For current measurement, most meters must be placed in series with the circuit, and high-current inputs may require dedicated jacks or separate meters.

Digital multimeters became widely used in the 1970s and 1980s, and today are common in electronics repair, electrical installation, automotive diagnostics, and laboratory work.