Hi guys,I'm Aabhishek sharma,today i came with my new instructable of making a touch sensor/touch sensitive switch,the current is passed through our body and the NPN transistor is turned ON when current is passed out through our body to the base of transistor and the LED glows.For youtube video link click here.
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Step 1: Materials and the Circuit
1. Transistor 2N2222A -1 pcs
2.100-200ohm resistor 1/2w -1pcs
3.LED-red any color-1pcs
4.6V TO 9V POWER SUPPLY (from battery or dc power supply,etc)
5.Some small pieces of metal sheet(for touch pad)
The circuitry used here is having a single NPN transistor acting as a current signal amplifier so that dc could be passed throuh our hand or body easily from battery positive to the transistor base making it turned on(switched on) so that the LED starts glowing.
The materials are listed above and also in the circuit diagram but a video can help more so i have added a link to youtube video in intro as well as in last step.
Step 2: Completed Circuit and Making Touch Pad
Have a look at the completed design ,i have added the metal strips in the form of finger touchpad .Arranged like two strips connected to one wire and other two strips to the other wire to be touched,so that when they are touched the current passed and LEDs glow.