Basic Terminology and Definitions of Multimeters
Accuracy
Indicates the deviation between the measured value of a digital multimeter and the true value. It is expressed as a percentage of the reading or a percentage of the full scale.
Analog Meter
An instrument that displays measured values by means of a mechanical pointer. The user reads the measurement according to the pointer position on the scale.
Annunciator
Used to indicate range selection status or functional errors.
Average‑Responding Digital Multimeter
Capable of accurate measurement for sinusoidal waveforms, but lacking sufficient accuracy when measuring non‑sinusoidal signals.
Count
The least significant digit on a digital multimeter. It is commonly used together with percentage values to specify instrument accuracy.
Current Shunt
A low‑value resistor inside a digital multimeter dedicated to current measurement. The meter measures the voltage drop across the resistor and calculates the current using Ohm's law.
DMM (Digital Multimeter)
Displays measured signals in digital form. Digital multimeters feature higher accuracy, resolution and reliability compared with analog meters.
Non‑Sinusoidal Waveform
Waveforms such as pulse trains, square waves, triangular waves, sawtooth waves and peaked waves.
Resolution
The smallest detectable change that can be observed during measurement.
RMS (Root Mean Square)
The AC signal magnitude equivalent to the value of a DC signal producing the same thermal effect.
Sinusoidal Waveform
An undistorted signal varying strictly according to the sine law.
True‑RMS Digital Multimeter
A digital multimeter that can accurately measure the RMS value of both sinusoidal and non‑sinusoidal waveforms.
