Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

Low cost intercom using transistors

Low cost intercom using transistors

The circuit comprises a 3-stage resistor-capacitor coupled amplifier. When ring button S2 is pressed, the amplifier circuit formed around transistors T1 and T2 gets converted into an asymmetrical astable multivib-rator generating ring signals.
These ring signals are amplified by transistor T3 to drive the speaker of earpiece. Current consumption of this intercom is 10 to 15 mA only. Thus a 9-volt PP3 battery would have a long life, when used in this circuit.

For making a two-way intercom, two identical units, as shown in figure, are required to be used. Output of one amplifier unit goes to speaker of the other unit, and vice versa. For single-battery operation, join corresponding supply and ground terminals of both the units together.

The complete circuit, along with microphone and earpiece etc, can be housed inside the plastic body of a cellphone toy, which is easily available in the market. Suggested cellphone cabinet is shown.

Visit Here for more.

 

More Articles to Read

Vertical Pole Climbing Robot
Vertical Pole Climbing Robot
ESP8266 Weather Station Projects
ESP8266 Weather Station Projects
Single tube Lethal Nixie clock
Single tube Lethal Nixie clock
How to make a simple 1 watt audio amplifier (LM386 based)
How to make a simple 1 watt audio amplifier (LM386 based)
Flashing Binaries to DRA7xx Factory Boards Using Device Firmware Upgrade
Flashing Binaries to DRA7xx Factory Boards Using Device Firmware Upgrade
Dot² isn’t your typical coffee table
Dot² isn’t your typical coffee table
Debugging ARM Cortex-M0+ HardFaults
Debugging ARM Cortex-M0+ HardFaults
EMP Jammer build
EMP Jammer build
A 3D-printed e-drum pad
A 3D-printed e-drum pad
Interactive geodesic LED dome = extreme geometric fun!
Interactive geodesic LED dome = extreme geometric fun!

Top




Shares