An analog VU (volume unit) meter is a type of meter that is used to measure the average level of audio signals. It is called "analog" because it uses mechanical movement to display the level of the audio signal, as opposed to a digital meter which uses numerical values to represent the level.
Analog VU meters typically consist of a needle or pointer that moves across a calibrated scale, with markings for different levels of audio. The needle or pointer will move in response to the audio signal, indicating the average level of the signal.
VU meters are designed to respond to audio signals in a way that mimics human hearing, taking into account the way our ears perceive loudness and volume. This means that a VU meter will respond differently to different types of audio, such as speech and music, and will indicate the appropriate level for each.
In summary, an analog VU meter is a type of mechanical device that measures and displays the average level of audio signals by physically moving a needle or pointer in response to the audio signal across a calibrated scale.