simple touch switch circuit


Posted on Feb 6, 2014

Here is a project of a simple touch switch circuit. This circuit and can also be used to activate a relay in the place of LED and resistor. The circuit is quite sensitive because we have used the two transistors as a Darlington pair. The gain is first amplified by the first transistor and then further amplified and multiplied by the second and so


simple touch switch circuit
Click here to download the full size of the above Circuit.

as a result we get a very high current gain. Due to high current gain the circuit can detect the very small current passing through our skin and activate the LED. The circuit can be operated with 6, 9 and 12 volts but make sure to use a proper LED current limiting resistor in the place of Rx. Use 330 ohms resistor for 6 volts, 390 ohms for 9 volts and 470 ohms for 12 volts Working of the circuit is simple; both the transistors are working as a switch. When you touch the touching points of the circuit a very small current starts passing through our skin which completes the circuit due to which the Darlington pair becomes switched on and light up the LED.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Baseband Circuits for an RFID Receiver
    RIAA Phono Equaliser
    Clock/Calendar/Alarm with ATtiny12
    Touch Switch with MPF102 JFET
    Input-buffered-mixer
    Digital Clock Circuit with T89C51 microcontroller
    Solar Cell Voltage Regulator
    Solid state voltage indicator with high voltage cutout
    Capacitance Meter
    Solar Panel Based Charger And Small LED Lamp
    Doorbell for the Deafs
    14-20dB gain simple active antenna circuit diagram
    M15m Tracking Transmitter
    Designing your own gear
    2W audio power amplifier LM380 circuit
    Electronic potentiometer circuit composed of digital circuits



    Top