Audio Circuit - Intercom

  1. 4-Way Intercom Schematic - The Link telephone intercom is designed around two ICs.
  2. Simple intercom schematic - The 8 ohm speakers is used as microphone and listening speaker.
  3. Homemade Intercom Schematic - Circuit suggestions for the Stereo Intercom. 
  4. Full-duplex Intercom - This design allows to operate two intercom stations leaving the operator free of using his/her hands in some other occupation, thus avoiding the usual "push-to-talk" operation mode.
  5. Use old phones as an intercom - This circuit will show how to use old phone as intercom.
  6. I.F.B Intercom circuit - Very useful type of intercom circuit.
  7. Intercom preamp - A very convenient way of making an intercom is to use a loudspeaker as a microphone.
  8. Op-amp as an audio amplifier for a simple intercom - A small 8 ohm speaker is used as a microphone which is coupled to the op-amp input through a 0.1uF capacitor
  9. Low-cost Transistorised Intercom - The circuit comprises a 3-stage resistor-capacitor coupled amplifier.
  10. Practical Intercom - This Intercom is powered by two 9volt batteries and uses only current when the Intercom is used.