Homemade Phone With Simple Electronic Circuits




About: I am a student of computer engineering

This project about communicating two people with basic electonic circuits. This is my Electronic circuits lesson's project. I want to make a video about it.

Here is a simple but effective intercom circuit that is basedfully on transistors.The circuit is based on a three stage RC coupledamplifier. When the pushbutton S2 is pressed, the amplifier circuit wiredaround T1 & T2 becomes an astable multivibrator and starts producing theringing signals. These ringing signals will be amplified by the transistor T3to drive the speaker. When the push button S1 is released the circuit willbehave as an ordinary amplifier and you can talk to the other side through it. To construct a two way intercom, make two identical copies ofthe circuit given below and connect it according to the given connectiondiagram. The stand by current consumption of this circuit is around 20mA.

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Step 1: Circuit Diagram With Parts List

Step 2: Connection Diagram

Step 3: Components


Assemble the circuit on a good quality PCB.Use 9V PP3 battery for powering the circuit.The Mic M1 can be condenser micro phone.Use push to ON type push button switch for S2.Use a slide switch for switch S1.S1 can be used to power the circuit.BEL 187 equivalent 2N2222, 2N4401, BC 548 You can replace BC548 with BC546, BC547, BC549, BC550

Step 4: How to Make

Drawing the circuit on the pcb

Step 5: Putting Components Into Pcb

Step 6: Soldering

Step 7: Cutting

Step 8: Putting Into the Box

Step 9: Soldering the Box

Step 10: Finish

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    2 Discussions

    KureBas RoboticsHarryY2

    Reply 1 year ago

    It is portable and there is no need to push the button to speak. You can speak without delay. The button give a voice like a ring. But the ring is not hearded in video. Because of background sound.