Electronic Circuit Analysis

38 Electronic Circuit Analysis
AI =-43.2
4S.3x(-44.S)xS
228.S+S
Vo Vo V 2
Ay = y=y- .y=A V2·A VI
1 2 I
Av = 0.99 x (-116.6) = -
lIS.
2.1.6 R - C Coupled Amplifier Circuit (Single Stage)
c~
Fig. 2.2 RC Coupled amplifier circuit
RL is the load resistor that develops the output voltage from the transistor. C 2
is used to couple
the AC component of the output to RL"
In the self bias circuit, RE the emitter resistors is connected between emitter and ground. Btit
through R E
, a negative feedback path is there. So to prevent A.C. negative feedback, if a capacitor is
connected in parallel with R E
, and it is chosen such that X E
provides least resistance path compared
to R E
, AC signal passes through C E
and not through R E
• Therefore, there will not be any negative
feedback for AC signals.
RE
X E is chosen such that XE ::; 10
1
and X E
is chosen at the frequency fi. For frequencies higher thanfi, X E
any way will be less.