Sound amplifier with LM386

Here is the circuit for the LM386, in order to amplify the signal from a microphone to build a sound sensor.

I have used two webpage as reference that were very useful for building the circuit. Actually, this circuit is almost the same that the one from Alex Tinkerlog:
DIY Tengu on a breadboard. Sound sensor


  • Arduino (only for power)
  • electret microphone
  • LM386 op-amp
  • 1 x 10k potentiometer
  • 1 x 100k potentiometer
  • 1 x 0.1uF capicitor
  • 1 x 220uF capacitor
  • 1 x 10uF capacitor
  • 1 x speaker

While using Arduino to power the circuit with the usb cable, there were a lot of noise coming from the speaker. As Alex says, if the circuit is powered with a battery, the noise disappear.