Manipal University 2007 A.M.I.E.T.E Electronics & Communication Engineering FIRST SEMESTER B.E END SEMESTER - Question Paper

FIRST SEMESTER B.E. DEGREE END SEMESTER EXAMINATION

Reg. No.

MANIPAL INSTITUTE OF TECHNOLOGY Manipal University, Manipal - 576 104 FIRST SEMESTER B.E. DEGREE END SEMESTER EXAMINATION December -2007 SUBJECT: BASIC ELECTRONICS (ECE - 101/102) (REVISED CREDIT SYSTEM)

MAX. MARKS : 50

Instructions to candidates

Answer ANY FIVE full questions.

Missing data may be suitably assumed._

IA.    List the characteristics of ideal OP AMP.    3

IB.    Simplify the following Boolean expression and realize using NAND gates

F = ( A + B + C ) ( A + B + C ) ( A + B)    3

IC.    What is amplitude modulation? Derive equation for AM output in time domain. Sketch sinusoidally modulated AM wave for modulation index m =1, m <1 and m >1 .    4

2A. Explain AND gate with help of a circuit using discrete components. 2B. Explain the need for modulation.

2C. Assume that a silicon transistor with P = 80, VCC = 16 V, RC=3.9 K RE =0.68K, R1 =62K and R2 =9.1K is used in voltage divider bias circuit. Determine the operating point.    4

3A. With the help of energy band diagrams classify solids. 3B. Define a and p. Derive the relationship between them

3C. Primary voltage to a transformer with turns ratio is 5:1 is 120V, 60Hz. This is applied to bridge rectifier employing 4 identical diodes with forward voltage drops 0.6V and forward resistance 15Q. The load resistance is 1kQ. Calculate average and rms load voltage, efficiency, ripple factor, PIV rating and frequency of output waveform.    4

4A. What is doping ? Compare P and N type semiconductors.

4B. Explain half adder with functional table and write logical expressions for sum and carry. Realize carry using NOR gates.

4C. i) For the zener regulator Vi= 16 V, R_S= 1 K, V_Z= 10 V and R_L= 3 K. Determine Vo, Iz and Pz

ii)Repeat with RL= 1K    4

5A. Perform the following

(i)    (257.75)₁₀ - (128.825)₁₀ using binary 2s complement arithmetic

(ii)    (ABCD)16 = ( ? )10 = ( ? )2 = ( ? )8    3

5B.Sketch the frequency response of RC coupled amplifier and mark the regions and indicate bandwidth    3

5C. A silicon diode has reverse sat current 12 nA at 20oC. (a) Find the diode current when it is forward biased by 0.65 V. Find the diode current when the temperature rises to 100oC.    4

6A. For a differential amplifier, the input voltages are v₁ =10 mV and v₂ = 8mV.

If the differential gain is 5000, Calculate the output voltage when the CMRR is 80 dB.    3

6B. Draw the circuit diagram of OPAMP adder and derive the expression for

output.    3

6C. With help of circuit diagram and waveforms explain working of center

tapped full wave rectifier.    4

ECE - 101/102    Page 2 of 2

Attachment: manipal-university-2007-a-m-i-e-t-e-electronics--amp--communication-engineering-3466-1.pdf

Earning:   Approval pending.