RTU Previous Year Question Papers
BE EC 4th Sem
Analog Electronics Communication July 2011
1 (a) Draw the block diagram of a negative feedback amplifier.
Derive an expression-for the voltage gain of an amplifier of gain A when subjected to negative feedback with a feedback fraction B.
(b) State the merits and demerits of negative feedback amplifier .
2 (a) Discuss the effect of negative feedback on :
(ii) Output impedance
(iii) Input impedance
(b) An amplifier with current feedback has the following specifications :
hfe = 100Q; hie = 2000Q, R, = 15000Q
R2 = 5600Q, Re = 100Q and RL = 470Q
Calculate the values of voltage gain and input resistance of the amplifier with and without feedback.
3 (a) Find an expression for the frequency of oscillations and condition for sustaining the oscillation in tuned collector oscillator.
(b) Describe Hartley oscillator circuit and explain its action.
4 (a) Sketch the circuit of schmitt trigger and explain its operation.
(b) What is a monostable multivibrator ? Explain its working with the help of neat waveform?
5 Draw the circuit diagram of emitter follower at high frequencies.- Also explain its behaviour at high frequencies with necessary expression and parameter.
6. Determine gain bandwidth product, unity gain frequency using hybrid n model for CE configuration. .
7(a) Sketch 2 – input XOR function using static CMOS circuit technique, assume complementary signals are not available.
(b) Explain with neat diagram the working of a totem pole two input TTL NAND gate.
(a) Explain the parameters used to characterize logic families..
(b) Write brief notes on ECL and RTL logic families.
8. (a)Draw the circuit diagram of a push – pull amplifier. Explain its operation. (b)Discuss its advantages and disadvantages.
(a) Show that maximum collector efficiency of class A transformer coupled power amplifier is 50%.
(b)What do you understand by class A, B and C power amplifiers?
Define and explain the following terms as applied to power amplifiers:
(i) Collector efficiency
(ii) Power dissipation capability
(iii) Overall gain.