What is a NPN Transistor?NPN Transistor DefinitionAn NPN transistor is a widely used type of bipolar junction transistor, where a P-type semiconductor layer is flanked by two N-type layers. Construction of NPN TransistorAs discussed above, the NPN transistor has two junctions and three terminals. The construction of the NPN transistor is as shown in the below figure. The emitter and collector layers are wider compared to the base. The emitter is heavily doped. Therefore, it can inject a large n