SPPU First Year Engineering (Semester 1)
Basic Electronics Engineering (BXE)
April 2013
Total marks: --
Total time: --
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Answer any one question from Q1 & Q2
1 (a) Sketch IR and VO w. r .t time for the network shown in fig. A. Assume both the diodes are silicon type with Vf=0.7 V

6 M
1 (b) For a BJT as a switch why CB and cc configurations are not preferred.
2 M
1 (c) Explain how Ri and Ro affect the performance of the BJT voltage amplifire.
4 M

2 (a) Explain with V-I characteristics the working of zener diode as voltage regulator.
6 M
2 (b) In the voltage amplifire shown in Fig B, Vs=100m V Rs=50 Ω
(i) Calculate input voltage Vi if the input resistance Ri is 600 Ω
(ii) What should be the value of Ri to get Vi=75 mV.

6 M

Answer any one question from Q3 & Q4
3 (a) In fig. C if Va=+2V Vb=+4V
Ra=Rb=R1 = 1K Ω and Rf=3 k Ω determine the voltage V1 at non-inverting terminal of OP-AMP and out voltage V0

4 M
3 (b) Draw the block diagram of full adder using two half adder, explain its working with proper expression for sum and carry.
6 M
3 (c) Explain how EX-OR gate can be used as an invertor.
2 M

4 (a) With neat waveform explain IC555 in astable mode.
6 M
4 (b) Implement the following logic expression with minimum number of NAND gate
(i) y1=B(D +C D)
(ii) y2=AB+CD+B C
6 M

Answer any one question from Q5 & Q6
5 (a) Explain in detail, the selection criteria for transducer.
6 M
5 (b) Explain in detail
i) construction of TRIAC
ii) characteristics of TRIAC
iii) modes of oper Ation
7 M

6 (a) Explain with block diagram an electronic weighing machine.
6 M
6 (b) Explain the construction of DIAC w.r.t
i) Characteristics
ii) Application
7 M

7 (a) What is the importance of modulation index. Draw the AM waveform for
i) Liner modulation
ii) Over modulation
iii) Modulation index = 0
8 M
7 (b) Explain the basic structure of mobile phone system.
5 M

8 (a) With respect to FM explain
i) Frequency deviation
ii) Modulation index
iii) Deviation ratio
iv) Frequency spectrum of FM
8 M
8 (b) Write a note on co-axial cable and optical fibre cable.
5 M

More question papers from Basic Electronics Engineering (BXE)