Question

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

Answer 1

Explanation:

1. A transistor is a semiconductor device that can conduct as well as insulate electric current or voltage. A transistor serves as both a switch and an amplifier. In layman's terms, a transistor is a small device used to control or regulate the flow of electronic impulses.
2. NPN transistors are three-layer bipolar transistors utilized for signal amplification. It is a device that is powered by the current. The abbreviation NPN refers to a negative-positive-negative transistor.
3. PNP transistors are transistors that have one n-type material doped with two p-type materials. It is a device that is powered by a current. The modest quantity of base current regulated both the emitter and collector currents.
4. The schematic symbols for NPN and PNP transistors are extremely similar. The sole distinction is the orientation of the arrow on the emitter. It points outward in an NPN (on the left) and inward in a PNP (on the right).

Therefore,

1. Step 1: Connect the positive lead of the multimeter to the transistor's base $\left(B\right)$and the negative lead to the transistor's Emitter$\left(E\right)$. If it is an NPN transistor, the voltage drop should be between $0.45V$ and $0.9V$on the meter. If it is a PNP transistor, it should show "$OL$" (Over Limit).
2. Step 2: Connect the positive lead to the transistor's base $\left(B\right)$ and the negative lead to the Collector $\left(C\right)\left(C\right)$. A decent NPN transistor will display a voltage drop between $0.45V$ and $0.9V$ in this setup. When testing a PNP transistor, you should observe "$OL$" (Over Limit).
3. Step 3: Connect the positive lead of the multimeter to the transistor's emitter and the negative lead to the transistor's base in this step. An NPN transistor will show an "$OL$" for this connection (Over Limit). In the instance of a PNP transistor, the meter shows a voltage decrease of $0.45V$ to $0.9V$.
4. Step 4: Connect the positive lead of the multimeter to the COLLECTOR $\left(C\right)$ of the transistor and the negative lead to the BASE $\left(B\right)$ of the transistor in this step. An NPN transistor will display an "$OL$" in this setup (Over Limit). A PNP transistor, on the hand, will show a voltage drop between $0.45V$ and $0.9V$.
5. Step 5: Connect the meter's positive lead to the Collector $\left(C\right)$ and the negative lead to the Emitter $\left(E\right)\left(E\right)$. A decent NPN or PNP transistor in this setup will show an "$OL$" Over the Limit on the meter.

Hence, this is the way to know if a transistor is NPN or PNP.