Today I am going to make simple touch sensor using BC547 transistor.When we will touch on the wire then LED will glow and as we will not touch on the wire then LED will not be glowing.
Let's get started,
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Step 1: Take All Components As Shown Below
Components required -
(1.) Transistor - BC547 x1
(2.) LED - 3V x1
(3.) Resistor - 1K
(4.) Battery clipper
(5.) Battery - 9V x1
Step 2: Pins of BC547 Transistor
This picture shows the pinouts of BC547 Transistor as you can see in the picture.
Step 3: Solder 1K Resistor
Firstly we have to solder 1K resistor to the collector pin of transistor as solder in the picture.
Step 4: Connect LED to the Circuit
Next we have to connect LED to the circuit.
Solder -ve leg of LED to 1K resistor as you can see in the picture.
Step 5: Connect Wire to Base Pin of Transistor
Next solder extra long wire to the base pin of transistor as solder in the picture.
Step 6: Connect Battery Clipper Wire to the Circuit
Now we have to solder the wires of battery clipper.
Solder +ve wire of battery clipper to +ve leg of LED and
Solder -ve wire of battery clipper to emmiter pin of the transistor as you can see in the picture.
Step 7: Connect Battery and Touch on the Wire of Circuit
Now our circuit is ready so connect 9V battery to the Battery clipper and touch with free finger on the +ve leg of LED and Base pin of transistor as you can see in the picture.
Now the result you can see in the picture.
# When we will touch on the pins with free hand then LED will glow and as we remove the finger then LED will not be glowing.