10 simple touch switch using transistor

This  circuit is no doubt one of the simplest touch switch circuit
using transistors configured in a Darlington form. When you touch
the touch plate, your hand will provide a several ohms of resistance
that is enough to make a close circuit between the base of the
transistor and power supply. Touching the plates lights the LED
up but it will automatically tuns off when plate is not touched.
Materials:
2 - general purpose transistor (9013, 2N222, others)
1 - 100k resistor 1/4 W
1 - 100 ohm resistor 1/4 W
1 - 6V to 9V battery
1 - LED (preferably red)



Note that  this touch switch circuit may not work properly when
the supply is a rectified dc from an ac source.
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10 comments:

  1. AnonymousNovember 16, 2010 at 11:19 PM

    nice circuit...

    ReplyDelete
  2. UnknownMarch 24, 2011 at 11:05 PM

    Excuse me, what do you mean by touch plate? how can i make this?or should i buy this thing?

    ReplyDelete
  3. DH-gmMarch 25, 2011 at 3:32 PM

    Saidaliah good day!
    touch plate or touch pad. its just a piece of of any conductor formed like the figure above.The main purpose of this is when you touch, your finger will acts as a conductor that will connects the two wires.
    When making touch plate,just copy the diagram above using cooper in a pcb but make sure that this wires are not separated.You dont have to buy, just any piece of conductor that is formed like above diagram will do.

    ReplyDelete
  4. FranzemyllMay 4, 2011 at 7:42 AM

    hello DH-GM, how can i make this circuit a little complicated? Like for example, if i touch the switch, the led will light and turn off only when i touch the switch again. thAnks!!=)

    ReplyDelete
  5. sushmaMay 4, 2011 at 8:08 AM

    SIR,
    WHAT IS TOUCH SWITCH AND GIVE ME LITTLE BRIEF EXPLANATION REGARDING IT.

    ReplyDelete
  6. DH-gmMay 6, 2011 at 3:30 PM

    To Franzemyll,
    This simple circuit is made just to show how a transistor work and what are the possible use.
    Based on your question, i assume you are referring to a flip flop circuit. I have circuit that is similar to what you ask. i recommend to view it and even modify it. Link below
    Clap Switch

    ReplyDelete
  7. DH-gmMay 6, 2011 at 3:36 PM

    To Sushma.
    When you touch the touch plate, your body provides continuity to the circuit thus turning on the transistor.

    ReplyDelete
  8. sushmaMay 6, 2011 at 9:18 PM

    sir,
    thank you sir,and also i want to know about the working of the mobile cell phone charger.

    ReplyDelete
  9. AnonymousApril 30, 2012 at 11:01 AM

    can i use other transistor .....? If yes mention the value of transistor

    ReplyDelete
  10. UnknownFebruary 21, 2013 at 12:36 AM

    What if the touch plate is not connected to the power supply only connected below to the resistor, and so on. Will that work if the touch plate is touched?

    ReplyDelete

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