UNIT I

SINGLE STAGE AMPLIFIERS :  

Small Signal Analysis of Junction Transistor using h-parameter model, Frequency Response, Effect of bypass Capacitor and Coupling Capacitor on Frequency Response, Analysis of JFET Amplifiers- Common Source, Common Drain, Common Gate Amplifiers

REFERENCE BOOKS :

1.       Integrated Electronics – J. Millman and C.C. Halkias, McGraw-Hill, 1972.
2.       Micro Electronic Circuits – Sedra A.S. and K.C. Smith, Oxford University Press, 5th ed.
3.       Electronic Devices and Circuits - Theodore F. Bogart Jr., J. S. Beasley and G. Rico,  
          Pearson Edition,  6th Edition, 2004.
4.       Electronic Circuit Analysis and Design – Donald A. Neaman, McGraw Hill  


LECTURE  NOTES :

1.  Difference between Small signal and Large signal amplifiers.
2.  Introduction to h - Parameter model and its equalent circuits for CE, CC and CB configuration.
3.  How to convert given circuit into a generalized circuit, to perform small signal analysis.
     a. Common Emitter amplifer with bypassed Re
     b. Common Emitter amplifier with Colletor to Base resistor (Millers Theorem)
     c. Common Emitter amplifier with un bypassed Re (Dulality of Millers Theorem)
     d. Common Collector (Emitter Follower) amplifier
     e. Common Base amplifier
4.  Small signal analysis of generalized amplifier circuit. (Calculation of Ai, Zi, Zo, Av, Avs and Ais) 
5.  Conversion of h-parameters and Typical h-parameter values
6.  Examples (using exact h-parameter model)
7.  Necessary conditions for Approximate (Simplified)  h-parameter model
8.  Small signal analysis of Common Emitter amplifier (with Ce) using Simplified model
9.  Small signal analysis of Common Emitter amplifier (with Re) using Simplified model
10. Small signal analysis of Common Collector amplifier
11. Small signal analysis of Common Base amplifier
12. Comparison of CE, CC and CB amplifier
13. Examples (using simplified hybrid parameter model )

14. Importance of Frequency Response, effect of µF capacitors and pF capacitors

15. Response of Common Emitter amplifier at Mid Frequencies (MF analysis)

16. Response of Common Emitter amplifier at Low Frequencies (LF analysis)
      a. effect of blocking capacitor,Cb
      b. effect of blocking capaciotr, Cc
      c. effect of emitter bypass capacitor, Ce 

17. Response of Common Emitter amplifier at High Frequencies (HF analysis)

18. JFET small signal model

19. Small signal analysis of Common Source amplifier with and without Rs.

20. Small signal analysis of Common Drain amplifier with and without Rd.

21. Small signal analysis of Common Gate amplifier 

ASSIGNMENT - I (Theory) :

1. Write the advantages of h-parameters ?

2. Explain how Common Emitter h-parameters can obtained from its input and output characteristics.

3. Using simplified model of h-parameters, Derive the expressions for current gain, input impedance,  voltage gain, and output impedance for
   (a)  Common Emitter amplifier with emitter bypass capacitor.
   (b) Common Emitter amplifier with emitter resistor.
   (c) Compare (a) and (b)

4. What is the condition for using simplified model. Explain.

5. Can we use simplified Common Emitter model for the analysis of Common Collector and Common Base amplifier. Justify your answer with explanation.

6. Draw the small signal equivalent of JFET at Low Frequencies and High Frequencies.

7. Derive expressions for voltage gain, input impedance and output impedance for
    (a). Common Source amplifier with out resistance at source terminal.
    (b) Common Source amplifier with resistance at source terminal.
    (c) Compare (a) and (b)

8. Derive expressions for voltage gain, input impedance and output impedance for
    (a) Common Drain amplifier with out resistance at Drain terminal.
    (b) Common Drain amplifier with resistance at Drain terminal.

9. Derive expressions for voltage gain, input impedance and output impedance for Common Gate amplifier.

10. Explain frequency response of an amplifier and what parameters can be obtained from it.



ASSIGNMENT - II (Problems) :



Previous JNTU Questions :
1. Derive expressions for voltage gain and input impedance of a common source JFET amplifier with the help of its circuit diagram and its equivalent circuit.

2. For the common Emitter amplifier circuit shown, Find Av and Rin. Assume typical values of h – parameters for the silicon NPN transistor. Consider the emitter capacitors CE    to be open circuited for computation of Av and Rin.

3. For the CB amplifier circuit shown, compute RIN and ROUT if C1 is
      i) Connected                                    ii) Not connected 
   The h-parameters of the transistor in CE configuration are listed as:  

    hie = 2.1KΩ, hfe = 81, hoe = 1.66 µMhos and hre is negligibly small 

4. Reason out the causes and results of Phase & Frequency distortions in transistor amplifiers. 

5. Consider an emitter  follower and show that  as Re → ∞, 

6. State Miller's theorem and its dual.

7.  
 






Previous GATE Questions on Small Signal Analysis of BJT