Electronics & Telecomm. (Semester 3)
TOTAL MARKS: 80
1(b) For the circuit given below find ID, VDS, VGG
1(c) Write down current equation of diode and explain significance of each parameters.(4 marks)
1(d) Explain the concept of thermal runaway in BJT.(4 marks)
1(e) Draw the output Waveform Vo for circuit shown.
1(f) State and explain Barkhausen's criteria for oscillations.(4 marks)
2(a) Determine Q-Print and draw d.c. load line for the amplifier shown.
2(b) Derive the expression for frequency of oscillation for a BJT RC phase shift oscillator.(10 marks)
3(a) Determine voltage gain, Input resistance and output resistance for the MOSFET amplifier shown.
3(b) Explain the working and characteristics of -channel Junction Field Effect Transistors (JFET)(10 marks)
4(a) Draw the output waveform V0 for ckt shown if (i) Vr = 0V (ii) Vr = 0.7v where Vr is cutin voltage of diode.
4(b) For the common base circuit shown, the transistor has parameters β = 120 and VA = ∞
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.
1(a) Find Vε and IE for the circuit given below
(i) Determine the quiescent VCEQ
(ii) Determine the small signal voltage gain and output resistance.
5(a) For the Amplifier shown determine (i) Q point (ii) Av, Zi, Zo
5(b) Derive expression for voltage gain, input resistance and output resistance for source follower circuit using n-channel MOSFET.(10 marks)
Write short notes on any Four
6(a) Construction and operation of varactor diode.(5 marks)
6(b) MOS capacitor(5 marks)
6(c) Transistor as a switch(5 marks)
6(d) Crystal oscillator(5 marks)
6(e) Hybrid-&pi(5 marks)