MIC Pre-amplifier

Rajkumar Sharma      http://www.rajkumarsharma.com  
Project tested


This project is a microphone pre-amplifier based on LM358.


This is easy to construct microphone pre-amplifier project using compact electret condenser microphone. The pre-amplifier is important building block of many audio communication systems. Circuit has been built around Op-Amp LM358.

  • Power supply : 5 to 12 VDC @ 10 mA
  • Output: Gain Approx. 100
  • On-Board electret condenser microphone
  • Header connector for connecting of power supply input and audio output
  • Power-On LED indicator
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 35 mm x 40 mm


Parts List


4 Response on “MIC Pre-amplifier

    1. The mic output is in the range of mV and needs a bias resistor R2 in order to work. In addition you can feed a small signal like that directly on C3 and omit R2 resistor so you get an amplified signal on the output.

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