Let’s take a closer look at how NPN and PNP transistors work. There are two main types of transistor: bipolar junction transistors (BJTs) and field effect transistors (FETs). BJTs are made of ...

Just like with NPN and PNP transistors, there are N-FETs and P-FETs. N-FETs are like NPN transistors – the gate pin needs to have higher voltage than the source pin for the FET to open.

Imagine for a moment a simple transistor circuit involving a single NPN transistor with its emitter grounded, its collector tied to the positive supply by a resistor, and a potentiometer between ...

The npn and pnp transistors used in the circuit should be high current- gain (hfe > 100) devices with minimum 2-A continuous current drive capacity (see the figure). This ensures an output stage ...