Understand Electronics, 2nd Edition

8

Transistors

Transistors of various types form the basis of most electronic circuits. As we shall explain later, there are two fundamental applications for transistors — as electronically controllable switches and as amplifiers. We describe several different types of transistor in this chapter, beginning with the MOSFET field effect transistor, which is the easiest to understand.

MOSFETs

The action of a field effect transistor depends upon the effect of the field produced by a charged region known as the gate. The term MOSFET is the acronym for metal oxide silicon field effect transistor. The diagram opposite shows why the transistor has this description. The transistor is based on a bar of p-type silicon. Two crosswise strips in the bar are doped ...