multimetr

A multimeter, sometimes spelled multimeter or multimetr, is a handheld electronic measuring instrument that can test multiple electrical properties. The most common variants are digital multimeters (DMMs) and analog multimeters. They are used by electricians, technicians, and hobbyists to diagnose circuits and verify electrical parameters. Most meters are battery-powered handheld devices with a display and a set of leads for probing circuits.

Typical functions include measuring direct and alternating voltage (V), direct and alternating current (A), and electrical resistance (Ω). Many models offer additional tests such as continuity check, diode testing, capacitance, frequency, and temperature via a thermocouple. Modern DMMs often feature auto-ranging, where the instrument selects the appropriate scale, and data hold to freeze a reading.

Operation involves several principles. Voltage is measured with a high input impedance to avoid loading the circuit; current is measured by inserting the meter in series using a built-in shunt; resistance is determined by applying a small current and measuring voltage, then applying Ohm’s law. Some meters provide true RMS measurement for AC signals, while others use average-responding methods.

Safety and use considerations include the meter’s rating, often described by a CAT safety category, indicating safe working voltage and environment. Proper probe use, correct range selection, and de-energizing circuits as required are important. Multimeters are widely used in electronics, automotive diagnostics, and electrical installations to quickly assess health and operation of electrical systems.