SPPU First Year Engineering (Semester 1)
Basic Electronics Engineering (BXE)
October 2012
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) A diode used as half wave rectifire, whose internal resistance is 20? is to supply power to a 1000? load from a 110Vrms Source of Supply.
(i) the peak load current
(ii) the dc load current
(iii) the dc load current
6 M
1 (b) (i) Sketch the CE output characteristics and indicate the active, saturation and cut-off regions.
3 M
1 (b) (ii) Sketch a family of CE input characteristics and explain the shape of these curves qualitatively.
3 M

2 (a)

Refer the circuit diagram of Fig. 1
(i) Idenify the circuit.
(ii) Calculate voltage across capacitor C1 and C2.

6 M
2 (b) Explain CE transistor as a switch and why CB and CC configurations are not preferred as a switch.
6 M

Answer any one question from Q3 & Q4
3 (a)

Determine the gain and output voltage of the amplifier in fig. 2. Assume ideal Op.-Amp

6 M
3 (b) Realize EX-OR gate using NAND only.
3 M
3 (c) Prove the following using Boolean Algebra:
A+ A ?B+A? B=A+B
3 M

4 (a) The timing component in square wave generator circuit using IC555 are RA=10K, RB=20K and C=0.01 ?F, Calculate:
(i) Frequency of Oscillation
(ii) Percentage Duty Cycle
6 M
4 (b) Draw a full adder circuit using two half adders. Use :
(a) Block diagram of Half Adder (b) Circuit diagram of Half Adder
6 M

Answer any one question from Q5 & Q6
5 (a) Explain the construction, working and characteristics of SCR.
6 M
5 (b) Draw constructional details of LVDT. Explain its operation. State its advantages and disadvantages.
7 M

6 (a) Draw block diagram of Electronics Weighing Machine and explain its operation.
6 M
6 (b) Explain the construction, working and characteristics of TRAIC.
7 M

Answer any one question from Q7 & Q8
7 (a) Draw and explain Electromagnetic Spectrum.
7 M
7 (b) Draw and explain the block diagram of GSM system.
6 M

8 (a) Define Modulation Index and explain the effect of Modulation Index in FM.
6 M
8 (b) Write short note on Twisted Pair Cables and explain problem associated with Twisted Pair Cables.
7 M

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