Electronic Devices and Circuits: Unit II: Amplifiers
Frequency Response of Multistage Amplifiers
Need for Multistage Amplifiers: 1. When amplification of single stage amplifier is not sufficient. 2. When input or output impedance is not of correct magnitude for the intended application. 3. To increase the overall gain.
FREQUENCY RESPONSE OF MULTISTAGE AMPLIFIERS
Need for Multistage Amplifiers
1.
When amplification of single stage amplifier is not sufficient.
2. When input or output impedance is not of correct magnitude for the intended application.
3.
To increase the overall gain.
Consider
the cascading of 'n' CE amplifier stages as shown in Fig. 2.34.
Voltage Gain
The
voltage gain of the cascaded amplifier is defined as the product of the
individual voltage gains of each stage.
Total
voltage gain is written as
The
magnitude of voltage gain is the product of the magnitudes of the voltage gain
of each stage. The phase shift is the sum of phase shift introduced by each
stage.
The
voltage gain can be expressed in terms of current gain as
The
current gain and input impedance of the nth stage is given by
The
current gain and the input impedance can be calculated at every stage by
replacing 'n' by the corresponding stage.
Electronic Devices and Circuits: Unit II: Amplifiers : Tag: : - Frequency Response of Multistage Amplifiers
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Related Subjects
Electronic Devices and Circuits
EC3353 - EDC - 3rd Semester - ECE Dept - 2021 Regulation | 3rd Semester ECE Dept 2021 Regulation