Page 980 - Basic Electrical Engineering

Figure 14.19 Circuit diagram for determining the common-emitter transistor characteristics

Figure 14.20 (a) Common-emitter input characteristics; (b) common-emitter output characteristics

14.7.4 Transistor As an Amplifier

In Fig. 14.21 is shown a simple transistor amplifier circuit using an n–p–n
transistor connected in the common-emitter configuration. The ac signal

which is to be amplified is connected to the base circuit as shown. The output
is taken across a resistance, R in the collector circuit. The base circuit dc
L
voltage, V is such that the base will always remain positive irrespective of
BB
the magnitude of the input ac signal. The voltage, V is the summation of dc
BE
voltage V and the ac input signal, V . The dc voltage, V is the bias
BB
BB
i