multimetrin

Multimetrin, commonly called a multimeter in English, is a versatile handheld instrument used to measure electrical properties. It typically combines a voltmeter, an ammeter and an ohmmeter in a single device, and may also offer tests for continuity, diode function, capacitance, frequency and sometimes temperature.

There are analog and digital multimeters. Digital multimeters (DMMs) display numeric results, while analog models use a moving needle on a scale. Modern DMMs often include features such as auto-ranging, true RMS conversion for AC signals, data hold, backlight and min/max recording.

Construction and operation: A multimeter comprises input jacks, test probes, a sensing circuit, and a display. For voltage and resistance measurements, the device is connected across the component; for current, it must be placed in series with the circuit. The common jacks are COM and V/Ω/mA, with a separate high-current jack for larger currents. Safety features include fuses and protective circuitry to guard against overvoltage and improper use.

Accuracy and limits: Basic accuracy varies by model, typically around 0.5% to 1% for many DMMs. High input impedance minimizes circuit loading on voltage measurements; resistance and continuity tests require the circuit to be de-energized. True RMS meters provide more accurate results for non-sinusoidal waveforms, and some models offer additional measurements such as capacitance, frequency and temperature.

History and use: Multimeters evolved from galvanometers and moving-coil meters, with digital variants becoming mainstream in the 1970s. They are widely used in electronics repair, electrical installation, automotive testing and laboratory work.