Wednesday, 30 July 2014

Build Your First Robot - Transistors and Their Applications

As we know, a transistor generally has 3 pins - emitter, base and collector. The base is where the input signal is fed. The transistor acts as a switch and on receiving the input signal, it allows the current to flow from the collector to the emitter. As I have mentioned earlier, transistors work in a very narrow range of power supply, hence resistors must always be used with them to protect them from getting burnt. Now let's build our first circuit. This circuit will switch on an led when you touch the two ends of a wire.

In this circuit we will be using a BC547 transistor which is n-p-n. The longer leg of the led must be connected to the positive terminal of the battery and the shorter side must be connected to the collector of the transistor. Connect a wire to the positive side of the battery and another to the base of the transistor. A resistor of 150 ohms is connected in series with the emitter of the negative rail of the breadboard. Your first transistor circuit is done!

We will look at more of these kind of circuits in the future. If you have any kind of doubts or suggestions, feel free to comment.