Why base current of a PNP transistor is too small while comparing with collector and emitter current explain?

The base region is thin and lightly doped. Due to this, only a few of the large number of electrons emitted from heavily doped emitter recombined with holes in the base region, and hence base current is very low.

What is the difference between a PNP and an NPN transistor?

An NPN transistor has a piece of P-type silicon (the base) sandwiched between two pieces of N-type (the collector and emitter). In a PNP transistor, the type of the layers are reversed. NPN and PNP transistors have very similar schematic symbols. The only difference is the direction of the arrow on the emitter.

What in the direction of the current flowing through the base of PNP transistor?

The direction of current in PNP transistor is from the emitter to collector. The letter of the PNP transistor indicates the voltage requires by the emitter, collector and the base of the transistor. The base of the PNP transistor has always been negative with respect to the emitter and collector.

Why is the emitter of a transistor heavily doped?

The reason the emitter is the most heavily doped region is because it serves to inject a large amount of charge carriers into the base, which then travels into the collector, so that switching or amplification can occur. In npn transistors, the n-type emitter injects free electrons into the base.

What does the PNP transistor do?

PNP transistors are used to source current, i.e. current flows out of the collector. PNP transistors are used as switches. These are used in the amplifying circuits. PNP transistors are used when we need to turnoff something by push a button.

Why is emitter heavily doped?

Why we prefer NPN transistor instead of PNP?

The majority charge carriers in an NPN transistor are electrons and the majority carriers in a PNP transistor are holes. The electrons have better mobility than holes. Therefore, NPN transistors are preferred over PNP transistors.