How do you know if a transistor is NPN or PNP?

Hint:We can know if the transistor is NPN or PNP by using a digital multimeter. For accurate results, it is suggested to remove the transistor from the circuit first. NPN transistor is a negative-positive-negative transistor and PNP transistor is a positive-negative-positive transistor.

Complete step by step solution:
Both the types of transistors have the following three terminals:
- a Collector (C)
- an Emitter (E)
- and a Base (B)

Now, if one has to differentiate between the two to determine their identification, one can follow the following steps:
1. A NPN transistor shows a drop in voltage from 0.45V to 0.9V and PNP transistor shows overlimit (OL) when positive lead of the multimeter is connected to Base and negative lead to Emitter.

2. NPN transistors show drop in voltage between 0.45V and 0.9V and PNP transistors show OL when positive lead of the multimeter is connected to Base and negative lead is connected to the Collector.

3. Now, we connect positive lead to Emitter and negative lead to Base. A NPN transistor will show OL and PNP transistor shows a voltage drop between 0.45V and 0.9V.

4. Here, we connect the positive lead of the multimeter to Collector while connecting negative lead to Base. For this case, the NPN transistor shows OL and PNP transistor shows a voltage drop between 0.45V and 0.9V.

Note: This is how one can differentiate between NPN and PNP transistors, based on a multimeter test. NPN (Negative-Positive-Negative) transistor configurations is the most widely used type of Bipolar Junction transistors (BPJ) in the present world. They are generally made up of semiconductor