Schema electroncia - Intercom without microphone

How to build an intercom without a microphone?

Reading time: 2 minute

What does the project present?

The DIY project in the article presents the scheme of a simple intercom made with LM386 integrated circuit. The two 8-ohm speakers are used as microphones at the same time.

The LM386 is used as a power amplifier for 8-ohm speakers. The 10K potentiometer is used for volume control, and the gain gain can be adjusted from the 5K semi-adjustable.

from DPDT switch (double pole, double throw) the two positions "listener" and "listened" are reversed, thus achieving bidirectional communication.

How do DPDT switches work?

DPDT switches have six connectors, two inputs and four outputs that allow you to connect or disable switching circuits A and B together.

Electronic intercom diagram

List of required components

  • R1 = 270K
  • R2 = 27K
  • C1 = 100 uF
  • C2 = 10 uF
  • C3 = 200 uF
  • C4 = 47 nF
  • POT1 = 10K
  • POT2 = 5K
  • IC1 = LM386
  • S1 = single switch (normal ON / OFF)
  • S2 = DPDT switch
  • DIF1, DIF2 = 8 Ohm speakers
  • BAT1 = 9V battery + socket

Technical specifications of the LM386 integrated circuit

  • Battery operation;
  • Minimum external parts;
  • Wide supply voltage range: 4V – 12V or 5V – 18V;
  • Low quiescent current drain: 4 mA;
  • Voltage gains from 20 to 200;
  • Ground referenced input;
  • Self-centering output quiescent voltage;
  • Low distortion.

Bibliography:

https://www.electroschematics.com/
https://circuits-diy.com/
Dominte Claudiu (Romanian translation)

 622 total hits, 1 hits today

4 comments

  1. I'm amazed, I must say. Rarely do I encounter a blog that's equally educational and amusing, and without a doubt, you have hit the nail on the head. The issue is something which not enough people are talking intelligently about. Now i'm very happy I stumbled across this during my search for something concerning this.

Add a comment

Your email address will not be published. Required fields are marked with *