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How to Make a Touch Switch – Basic Electronics Projects – Breadboard Circuits

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Hi, welcome to Elonics! In this video I’ll
show you how to make a touch switch the components you need to build this circuit are 2 npn transistors i’m using BC547
transistors here A 270 ohm resistor 100 KOhm resistor an LED 2 breadboard connectors breadboard and a 6V power supply place both the transistors on the breadboard you can see the pin-out of the BC547 transistor which i’m using here the first pin is a collector the second
pin is the base and the third pin is the emitter now connect the base of the second transistor to the emitter of
the first transistor place the LED on the breadboard with the positive terminal connected to the
positive rail and the negative terminal will be connected to the collector of
the second transistor via the 270 Ohm resistor now connect the 100 KOhm
resistor between the collector of the first
transistor and the positive rail Now connect the emitter of second transistor to the ground now you need to connect two metallic
conductors one to the collector of the first transistor and the other to the
base of the first transistor known as you see when I when I touch both the metal wires with
my finger the LED starts glowing so what’s happening here is when I touch body metal wires the current flows from the 100KOhm resistor to the base of the first transistor which gets amplified and then it’s sent to the
base of the second transistor which is again magnified and it’s connected to
the LED so the tiny current that is passing
through the metal wires when I am placing my finger is getting magnified
about 200×200 times by the first and second transistor which is then sent to
the LED so whenever I touch the metal wires the LED starts glowing Thanks for watching Subscribe to my channel check out my other videos Thank you

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