AMIETE – ET/CS/IT (NEW SCHEME)   –   Code: AE53/AC53/AT53

 

Subject: ELECTRONIC DEVICES & CIRCUITS

Flowchart: Alternate Process: JUNE 2010Time: 3 Hours                                                                                                     Max. Marks: 100

 

NOTE: There are 9 Questions in all.

·      Question 1 is compulsory and carries 20 marks. Answer to Q.1 must be written in the space provided for it in the answer book supplied and nowhere else.

·      Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.

·      Any required data not explicitly given, may be suitably assumed and stated.

 

 

Q.1       Choose the correct or the best alternative in the following:                                  (210)

       

             a. Percentage regulation of a voltage regulator is given by __________.

 

                  (A)                       (B)

                  (C)                       (D)

 

             b.  For a SCR, the two transistor analogy holds good when the SCR is in _________

 

                  (A) Forward Blocking State                  (B) Conduction state

                  (C) Both (A) & (B)                              (D) None

       

             c.  The maximum conversion efficiency of a transfer coupled Class-A amplifier is

(A)  75 %                                              (B) 50 %

                  (C) 95 %                                              (D) 78.5 %

 

             d.  Node defines 

 

                  (A) the point where two or more elements meet.                                                                

                  (B)  is a loop that does not contain any other loop within it.

                  (C) a traversal through elements.          

                  (D) None of the above

 

             e.  Common base forward short-circuit current gain given by 

 

(A)                                                  (B)

                  (C)                                                 (D)                                                                  

 

             f.   The disadvantage of complimentary symmetry circuit is

 

                  (A) it requires one power supply.         

                  (B)  it requires two power supply.

                  (C) it requires more than one power supply.                                                                      

                  (D) Both (B) and (C).

             g.  The most popularly used transistor biasing circuit is

 

                  (A) Fixed Bias                                      (B) Feedback Bias

                  (C) Potential Divider Bias                     (D) None

 

             h.  Feedback in an amplifier increases the input impedance from  to  because of

                  (A) positive feedback                           (B) shunt-current negative feedback

                  (C) series-current negative feedback     (D) shunt-voltage negative feedback

 

             i.   SSI technology includes ______number of gates on chip.

 

                  (A) Less than 10                                   (B) 10 to 100

                  (C) 100 to 500                                     (D) More than 100

 

             j.   In a RC-phase shift oscillator having three stages, which have equivalent resistors and capacitors, in order to satisfy Barkhausen criteria, should have a minimum gain of

                  (A) 6                                                    (B) 29

                  (C) 31                                                  (D) 49

 

 

 

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

 

 

 

  Q.2     a.   State and explain reciprocity theorem with example.                                            (6)

                  

             b.   Using Thevenin’s theorem find the current flowing through 4  resistor in the network of Fig.1; (All resistances in )                                 (10)

Text Box:

 

 

 

 

 

 

 

  Q.3     a.   Explain Zener diode as voltage regulator.                                                            (8)

            

             b.   For the diode circuit of Fig.2, find the diode current, the diode parameters are

Text Box:                    ,   .                 (8)

 

 

 

 

 

 

 

 

 

  Q.4     a.   Draw and explain Common Emitter Configuration.                                              (6)

 
 
             b.   For the JFET circuit shown in Fig.3 find IDQ, VGSQ and VDSQ  if VP = -4V,      IDSS= 8mA and VDD = 16V.                                                              (10)

 

 

 

 

 

 

 

 

 

       

 

 

 

 

 

  Q.5     a.   Derive an expression for Stability factor of a biasing circuit.       (8)

 

             b.   Consider the JFET circuit of Fig.4

                   (i)  Determine the resistance seen from terminal 2 and ground at low frequencies.

                   (ii)  Evaluate the resistance in part (i) for   and .                               (8)
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 


  Q.6     a.   Explain various distortions occurred in small signal amplifiers.                              (8)

 

             b.   Draw and explain the tuned amplifier and determine its quality factor.                  (8)

 

  Q.7     a.   Draw the transformer coupled power amplifier and calculates its maximum possible efficiency.                                                                   (8)

 

             b.   Calculate the maximum conversion efficiency of complimentary symmetry circuit amplifier.               (8)

       

  Q.8     a.   Explain Phase Shift Oscillator.                                                                            (8)

 

             b.   Write a short note on Crystal Oscillator.                                                             (8)

 

  Q.9     a.   What is an epitaxial layer and how is it grown?  Explain the necessity of this layer as a first step on the substrate.                                                                                                           (8)

 

             b.   Explain the electron beam lithography.  What advantages does it have over photolithographic process?                                                                  (8)