18ELN14/24
Visvesvaraya Technological University, Belagavi
MODEL QUESTION PAPER
1st/2nd Semester, B.E (CBCS 2018-19 Scheme)
Course: 18ELN14/24- BASIC ELECTRONICS Set no.1
Time: 3 Hours Max. Marks: 100
Note: Answer Five full questions selecting any one full question from each Module.
Question on a topic of a Module may appear in either its 1st or/and 2nd question.
Module-1 Marks
1 a Explain the operation of p-n junction diode under forward and reverse biased
condition
8
b Explain how Zener diode can be used as a voltage regulator 6
c A diode circuit shown below has E=1.5V, R1=10 ohm. By assuming Vf=0.7V, calculate If
for
rd 0
ii) rd 0.25 ohm
Fig.Q.1(c)
6
OR
2 a With a neat circuit diagram and waveform, explain the working of half-wave rectifier
and derive the expression for average load current.
8
b Explain briefly the operation of a capacitor filter circuit. 6
c Explain the operation of 7805 fixed IC voltage regulator. 6
Module-2
3 a Explain the characteristics of N-channel JFET. 8
b For E-MOSFET, determine value of ID, if ID 4mA, VT=4V and Vgs=8V. 4
c Explain the construction and working of P-channel enhancement type MOSFET. 8
OR
4 a Draw and explain the operations of SCR using 2-transistor equivalent circuit. 8
b Explain phase controlled application of SCR. 6
c Explain the operation of a CMOS inverter. 6
Module-3
5 a For an op-amp List the characteristics of an ideal op-amp and Draw the three
input inverting summer circuit and derive an expression for its output voltage.
8
b Define the terms
Slew rate
ii) CMRR
iii) Common mode gain AC of op-amp
6
c Design an adder circuit using an op-amp to obtain an output voltage of Vo=

6
OR
6 a Draw the working of an inverting op-amp. Derive the expression for its voltage gain. 8
b With a neat diagram, explain how an op-amp can be used as a differentiator. 6
c Find the output Vo of following op-amp circuit.
Fig.Q.6(c)
6
Module-4
7 a Explain the operation of BJT as an amplifier and as a switch. 8
b What is a feedback amplifier? Briefly explain different types of feedback amplifiers. 6
c Draw and explain the operation of a voltage series feedback amplifier and derive an
expression for its voltage gain with feedback.
6
OR
8 a Explain the Barkhausens' criteria for oscillations. 6
b Explain the operation of an RC phase shift oscillator. 6
c Explain the working of an Astable oscillator constructed using IC- 555 timer. 8
Module-5
9 a Convert the following.
(725.25)10=( )16
ii) (111100111110001)2= )10 )16
8
b Simplify the following expressions and draw the logic circuits using basic gates.
AB+ ´ AC+ A´B C
ii)
6
c Realize a full adder circuit using 2 half adders. 6
OR
10 a What is a multiplexer? Explain the working of 4:1 multiplexer. 6
b With the help of a logic diagram and truth table, explain the working of a clocked SR
flip-flop.
6
c What is a shift register? Explain the working of a 4-bit SISO shift register. 8