What names are applied to the two types of BJT transistors? Sketch the basic construction...

The basic construction of PNP transistor is shown in Figure 1:

The basic symbol of PNP transistor is shown in Figure 2:

In Figure 2, the symbol B denotes Base, E denotes Emitter and C denotes Collector.

In PNP transistor majority carriers are holes and minority carriers are electrons.

The basic construction of NPN transistor is shown in Figure 3:

The basic symbol of NPN transistor is shown in Figure 4:

In Figure 4, the symbol B denotes Base, E denotes Emitter and C denotes Collector.

In NPN transistor majority carriers are electrons and minority carriers are holes.

If the silicon is replaced by the germanium then the PNP BJT remains PNP and NPN BJT remains NPN, but the silicon transistor can be operated in high temperatures compared to the germanium transistor.

Hence, the PNP and NPN transistors are not changed when the base changed from the silicon to the germanium.