Maharashtra State Board of Technical Education 2011-3rd Sem Diploma Electrical Engineering (DEE) for in Electrical Engineering GroupSubject :- -Basic Electronics(12058) - Question Paper
MSBTE ques. paper for Diploma in Electrical Engineering Group
Third Semester
Subject :- -Basic Electronics(12058)
3 Hours/100 Marks Scat No.
21011
12058Instructions : (J) All questions are compulsory.
(2) Answer each next main question on a new page.
(3) Illustrate your answers with neat sketches wherever necessary.
(4) Figures to the right indicate full marks.
(5) Assume suitable data, if necessary.
Marks
Attempt any ten of the following : (2x10=20)
a) Define the terms : Rectification efficiency and Ripple factor.
b) What is a filter ? Why it is necessary in rectifier ?
c) Name the four operating regions of transistor.
d) What is a regulated DC power supply ?
e) Draw symbols of (i) JFET (n-channel) (ii) BJT (npn).
f) Define intrinsic and extrinsic semiconductor.
g) (Jive two examples of trivalent and pentavalent impurities.
h) Which filter is practically preferred to get pure DC o/p. and why ?
i) Why an ordinary junction transistor is called a bipolar transistor ? j) What is an unipolar device and give an example.
k) (jive any two advantages of IC voltage regulator over discrete regulator.
1) State any 2 applications of zener diode.
Attempt any four of the following : (4x4=16)
a) Draw and describe working of zener diode as voltage regulator.
b) Draw a circuit diagram of reverse biased PN junction diode. Why does diodes not conduct in reverse bias ?
c) Derive the relation between a and p with respect to BJT.
d) Draw output characteristics of CE configuration and show various regions.
e) Draw and explain frequency response of single stage amplifier in CE configuration. Also define Bandwidth.
f) Draw neatly center tap rectifier and explain its operation.
Marks
(4x4=16)
3. Attempt any four of the following :
a) Explain construction and working principle of LED.
b) Draw the circuit of full wave rectifier with LC filter. Explain with the help of waveforms.
c) Draw circuit diagram of transistorized series voltage regulator and explain its working.
d) Draw pin diagram of IC 723 and list its applications.
e) Classify amplifiers based on coupling. Draw the circuit of RC coupled amplifier and draw the frequency response of it.
f) Explain the construction of JFET with neat diagram.
4. Attempt any four of the following : (4x4=16)
a) Explain the voltage divider method of biasing of transistor with the help of circuit diagram.
b) Draw a circuit diagram to explain the forw'ard biased characteristics of PN junction diode.
c) Explain the need for biasing in transistor. List any two methods.
d) Draw transformer coupled amplifier. Write its working.
e) Compare R-C coupled amplifier and direct coupled amplifier (any 4 points).
f) Draw the V-I characteristics of UJT label it.
5. Attempt any four of the following : (4x4=16)
a) Draw the circuit diagram of direct coupled amplifiers and mention its advantages and disadvantages (two each).
b) Explain the effect of bypass capacitor (CE) on the amplifier circuit.
c) What do you mean by thermal runaway ? Mow it should be avoided ?
d) Give 2 advantages, disadvantages and applications of LED.
e) In common emitter configuration if p = 150, leakage current IHO = if base current is 0.2 mA, determine Ic and IE.
f) Explain the operation of npn transistor in the active region.
6. Attempt any four of the following : (4x4=16)
a) If maximum voltage across secondary of half wave rectifier is 30V then what should be PIV of diode.
b) Compare PN junction diode and LED.
c) Explain block diagram of DC power supply.
d) In a common base configuration current amplification factor is 0.9. If emitter current is 1mA. Determine the value of base current.
e) Draw the hybrid model for CE amplifier ckt and define two port n/w.
f) What is effect of coupling on : (i) gain (ii) BW ?
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