Question: What is the main difference between NPN and PNP transistors?

Options:

1. NPN transistors have a positive collector
2. PNP transistors have a negative emitter
3. NPN transistors use electrons as charge carriers
4. PNP transistors are always off

Correct Answer: NPN transistors use electrons as charge carriers

Solution:

NPN transistors use electrons as charge carriers, while PNP transistors use holes.