Today I am going to make a simple touch sensor using transistor BC547. This circuit is very easy and it is very interested circuit.
Let's get started,
Step 1: Take All Components As Shown Below
Components required -
(1.) Battery - 9V x1
(2.) Battery clipper x1
(3.) LED - 3V x1
(4.) Resistor - 470 ohm x1
Step 2: Solder Resistor and LED to the Transistor
Firstly solder 470 ohm resistor to collector of the transistor as shown in picture
and then solder negative wire of LED to the 470 ohm resistor as shown in the picture.
Step 3: Connect Battery Clipper Wire
Now solder battery clipper wire to the circuit as picture.
Solder +ve wire of battery clipper to the +ve of LED and
connect -ve wire of battery clipper to emmiter of the transistor as shown in the image.
Step 4: Circuit Is Ready
Now circuit is ready -
Connect 9V battery to the circuit and touch base wire of transistor and 470 ohm resistor wire as shown in picture.
Observation - After touching the circuit wire we observe that the LED is start glowing, as we remove hand to the circuit we observe that LED is turn off.This type this simple touch circuit is working.