How to Use Transistor as a Switch

We all know that transistors can be used as switches or amplifiers, this blog is an example of using a Transistor as a Switch.

made with tinkercad

Collector – Purple

Base – Blue

Emitter – Green

In this circuit the Positive Terminal of the LED is connected to the Positive power supply and negative of the LED is connected to the collector.

The emitter of the Transistor is Grounded.

The base of the Transistor is connected to the positive supply through a resistor.

As seen in the above image, the base is disconnected from the Positive power supply and the LED Switches OFF

So the base of the Transistor can be used as a switch for the LED.


The Base of the Transistor works as a Gate (Depletion region) between Collector and Emitter.

The gate can be opened by providing a voltage (Threshold Voltage)

And once the Threshold Voltage is reached, the gate is opened and the current passes through the Collector-Base-Emitter of the transistor and Glows the LED.

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