SEC1205 - ELECTRONIC CIRCUITS - I

SEC1205 ELECTRONIC CIRCUITS-I UNIT - 3 SMALL SIGNAL ANALYSIS OF FET AND MOSFET AMPLIFIERS

PREPARED BY: Dr.M.Vadivel PAGE : _ OF _

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SEC1205 - ELECTRONIC CIRCUITS - I

UNIT 3 SMALL SIGNAL ANALYSIS OF FET AND MOSFET AMPLIFIERS

Biasing of FET Amplifiers- Types- Small Signal Model of FET- Small Signal Analysis of CS-CD-CG

FET Calculation of Input Impedance-output impedance-voltage gain using small signal model-

MOSFET Biasing-Types-Small Signal Model of MOSFET-Small Signal Analysis of CS-CD-CG

MOSFET- Calculation Input Impedance-output impedance - voltage gain using small signal model

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3.1 Comparison of BJT and JFET

Table 1 shows the comparison of Bipolar Junction Transistor (BJT) and Junction Field

Effect Transistor (JFET).

Table 1. Comparison of BJT and JFET



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3.2 Introduction to Biasing of FET Amplifiers

3.3 Types of JFET Biasing Circuits

• Fixed Bias • Voltage Divider Bias • Self Bias

3.3.1 Fixed bias Circuit



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Fig. 3.2 Simplified Fixed Bias Circuit



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3.3.2 Voltage Divider bias Circuit



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3.3.3 Self bias Circuit



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3.4 Small Signal FET Models

3.4.1 Small Signal Low-Frequency FET Model



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3.4.2 Small-Signal High-Frequency FET Model

3.5 Field Effect Transistor Amplifier

3.5.1 Common Source Amplifier



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3.5.1.1 Analysis of Common Source Amplifier



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3.5.1.2 Effect of A.C. Load on Amplifier Parameters



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3.5.1.3 Effect of External Source Resistance on Voltage Gain



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3.6 Common Drain Amplifier

3.6.1 Analysis of a Common Drain Amplifier



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3.7 Common Gate Amplifier



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3.7.1 Analysis of a Common Gate Amplifier



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3.8 Comparison of n-channel and p-channel JFET

Table 2. Comparison of n-channel and p-channel JFET

3.9 Comparison of JFET and MOSFET

Table 3. Comparison of JFET and MOSFET



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3.10 Introduction to MOSFET

3.11 Comparison of D-MOSFET and E-MOSFET

Table 4. Comparison of D-MOSFET and E-MOSFET

3.12 Biasing Circuits for MOSFET

There are two biasing circuits for MOSFET namely D-MOSFET AND E-MOSFET.

3.12.1 Biasing Circuits for D-MOSFET



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3.12.2 Biasing Circuits for E-MOSFET

3.12.2.1. Feedback Circuit Bias



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3.12.2.2 Voltage Divide Bias



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3.13 Small Signal Model of D-MOSFET

3.14 Small Signal Model of E-MOSFET



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3.15 Common Source amplifier using E-MOSFET



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3.15.1 Analysis of Common Source Amplifier



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By considering the Load Resistance (RL)

3.16 Common Drain Amplifier using E-MOSFET



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3.16.1 Analysis of a Common Drain Amplifier



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3.17 Common Gate Amplifier using E-MOSFET

3.17.1 Analysis of a Common Gate Amplifier



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SEC1205 - ELECTRONIC CIRCUITS - I

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