Page 985 - Basic Electrical Engineering

Figure 14.24

I = β I
C
dc B

or,

Taking V = 0.7 V, V − I R = V BE
BE
i
B 1

or, V = V + I R
BE
B 1
i
−6
3
= 0.7V + 80.6 × 10 × 16 × 10 V
= (0.7 + 1.29) V = 1.99 V

14.8 FIELD EFFECT TRANSISTORS

Field effect transistors (FETs), like BJTs are used in amplifier and switching
circuits. FETs are of two types, namely, junction field effect transistor (JFET)

and metal oxide semiconductor field effect transistor (MOSFET). Unlike a
BJT, FET is a voltage operated device having virtually no requirement of any

input current. The two types of FET are described below.

14.8.1 Junction Field Effect Transistors

A JFET has been shown in the form of a block diagram in Fig. 14.25 along

with its symbol. A JFET is made of an n-type semiconductor material called