Description
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
Notes.
§ 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.
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