Electronic Circuit Analysis

224 Electronic Circuit Analysis
6.5.3 Circuit for Extending Low Frequency Range (Fig. 6.16)
(a) Kinks in frequency response
6.5.4 Low Frequency Equivalent Circuit with Transistor Replaced by a Current Source
6.5.5 Extension of High Frequency Range
(b) Equivalent circuit with current source
Fig. 6.16
Bandwidth ofa given amplifiers can be effectively increased by increasing h. (sinceh» jj)h can
be increased by decreasing C s . But there is a limit to which C s value can be reduced h can also be
increased by decreasing RL 1. But if RL 1 is reduced the mid band gain will reduc~ Therefore without
changing the value of C s and RL 1 and without decreasing the mid band gain, h can be increased by
compensating techniques.
There are two different methods:
(i) Series compensation
(ii) Shul'I:t compensation
This classification is depending upon character 'Inductance' is in series or in shunt with the
oad resistance in the a.c equivalent circuit.
where
m = 002L1R1 (R 1
is the resistance in series or the resistance of the coil itself)
00 2 is the upper cutoff frequency of the uncompensated amplifier.