there are several different types of transistors.
- 1. bipolar.
- 2. unijunction
the bipolar type is a solid state device composed of 3 layers of material. there are two types, the npn, and the pnp.
the unijunction type is divided into two major classes, the field effect, and the metal oxide.
the metal oxide type is further divided into metal oxide and insulated gate.
all types are made of silicon with added impurities to give the desired properties.
the transistor was invented in america at bell labs by Bardeen and Shockley.