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