Category Archives: Communication



Telephone Amplifier using LM386

The following diagram is the circuit diagram of telephone amplifier, build based small amplifier IC LM386. This is a easy build telephone amplifier There is no extra electrical power supply required to power up the telephone amplifier circuit, as it draws power from the telephone line itself. The amplifier will supply fairly very good volume… Read More »

Cut Phone Line Detector

This cut phone line detector circuit is used to detect whether your phone line is active or not. Components List: R1,R2,R3 = 22M Ohms R4 = 2.2M Ohms C1 = 0.47uF/250V Mylar caps D1 = 1N914, NTE519, or other small signal diode Q1 = 2N3904, NTE123AP Q2 = 2N3906, NTE159 Q3 = IRF510, NTE2382, MosFet

Ultrasonic Sensor Switch

Here is the circuit diagram of ultrasonic sensor switch. There are many methods of wireless switching such as by using infrared, AM/FM signal, bluetooth, etc. This is an alternate wireless switching by using ultrasonic sensor. The distance of switching range should be more than 10 meters. This circuit produces and transmits ultrasonic sound of frequency… Read More »





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