Make a Simple Touch Sensor With Your Own .

For making a simple touch sensor we have required just 3 components.

1 ) One Transistor (BC547)
2 ) One Resistor (47ohm)
3 ) One LED
and also a 9V battery.

Now connect the resistor with LED in series from the positive supply to the collector of
transistor. Choose a resistor that sets the current of your LED to around 20mA.
Now connect transistor terminal with negative terminal of supply. And now create two wires with exposed ends-so you can see the metal. One goes to the positive of supply and the
other will be the base of the transistor. And you know what you have done all the process.
Now just touch your finger with two wires you will see the LED light up! The reason is that
your finger acts as a resistor and will give enough current to the base of the transistor to
turn it on.