Pre Amp Mic

variable resistor of R5 to adjust the gain of op-amplifier IC LM358.
The LM358 has two op-amp module, you may build stereo audio pre-amplifier using single LM358.

Component list of simple preamp mic circuit:
R1, R3, R4 : 10K
R2         : 1K
R5         : 100K-1M Potensiometer
C1         : 0.1uF
C2         : 4.7uF/16V
IC1        : LM358 dual op-amplifier
Mic        : Electret Microphone

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