Audio level meter circuit

Audio Level Meter


A simple and low cost audio level meter circuit that can be used to measure the audio level of your sound source.This circuit is a valuable tool for those who are interested in audio circuits.

The circuit is designed with a flat frequency response in the range of 20Hz to 50Khz. Input sensitivity is 100mV for a FSD on a 100uA ammeter.The circuit is build based on on two common emitter amplifiers, the first stage has a preset resistor R3 (1K) which may be adjusted for a FSD. The last stage is biased to operate at about 1/2 the supply voltage for maximum AC voltage deflection. C2&C2 (10 uF) acts as a filters through which audio frequencies are passed . The full wave bridge rectifier converts the signal to a varying dc voltage. The meter will show this voltage as the output reading which is proportional to the input voltage level.

Audio Level Meter Circuit Diagram with Parts List

sound level meter-VU level meter


  • The meter reading is instantaneous and it will not provide you with a peak to peak reading.
  • To calibrate the meter, provide a 1Khz 100mV sine wave at the input and adjust R3 to get a full scale reading on the meter.
  • Use a well regulated & filtered 12 V supply for powering the circuit.

Comments are closed.