PNP Transistor Explained in 60(ish) Seconds

Added: 2026-05-20

[00:00:00]Unlike an NPN transistor, which has two N-type materials sandwiching a P-type material between them, a PNP transistor has two P-type materials with an N-type material between them. This difference in material is why they act differently.

[00:00:14]With NPN transistors, you may see how a small current flows into the base and exits through the emitter, controlling a larger current from collector to emitter. However, in a PNP BJT, the direction of current flow is reversed.

[00:00:28]Here, a small current actually flows out of the base, controlling a larger current flowing from the emitter to the collector.

[00:00:35]You can think of it as an inversion of our water spigot analogy. The concept is similar, but the flow direction is reversed. Just like with an NPN transistor, we have our three terminals: base, emitter, and collector.

[00:00:48]But with a PNP transistor, the emitter terminal is at a higher potential, or more positive, while the collector is at a lower potential, or less positive.

[00:00:57]This is opposite to the NPN transistor, where the collector was more positive.

[00:01:02]In this case, the base is also at a lower voltage than the emitter, allowing current to flow out of the base.