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Basic Electronics Engineering (BXE) : Question Paper Oct 2012 - First Year Engineering (Semester 1) | Pune University (PU)

## Basic Electronics Engineering (BXE) - Oct 2012

### First Year Engineering (Semester 1)

TOTAL MARKS:
TOTAL TIME: HOURS

### 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.
Calculate:
(6 marks)
1 (b) (i) Sketch the CE output characteristics and indicate the active, saturation and cut-off regions.(3 marks) 1 (b) (ii) Sketch a family of CE input characteristics and explain the shape of these curves qualitatively.(3 marks) 2 (a)

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

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

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

### Answer any one question from Q5 & Q6

5 (a) Explain the construction, working and characteristics of SCR.(6 marks) 5 (b) Draw constructional details of LVDT. Explain its operation. State its advantages and disadvantages.(7 marks) 6 (a) Draw block diagram of Electronics Weighing Machine and explain its operation.(6 marks) 6 (b) Explain the construction, working and characteristics of TRAIC.(7 marks)

### Answer any one question from Q7 & Q8

7 (a) Draw and explain Electromagnetic Spectrum.(7 marks) 7 (b) Draw and explain the block diagram of GSM system.(6 marks) 8 (a) Define Modulation Index and explain the effect of Modulation Index in FM.(6 marks) 8 (b) Write short note on Twisted Pair Cables and explain problem associated with Twisted Pair Cables.(7 marks)