SRM University 2007 B.Tech Electronics and Communications Engineering EC202- ELECTRONIC CIRCUITS – II - Question Paper

EC202- ELECTRONIC CIRCUITS – II


Unit- I -FEEEDBACK AMPLIFIER

1. What is feedback? elaborate the kinds of feedback?
2. Define positive feedback. elaborate its merits and demerits?
3. Define negative feedback. elaborate it merits and demerits?
4. What is the effect of negative feedback amplifier. State the function of every block.
5. Derive the relationship ranging from the transfer gain with feedback Af and that without feedback A.
6. What is loop gain?
7. What is sensitivity?
8. What is desensitivity?
9. What is the effect of input resistance of the amplifier with series feedback connection and shunt feedback connection?
10. What is the effect of output resistance of the amplifier with series feedback connection and shunt feedback connection?
11. Sketch the circuit of single stage CE Amplifier that uses Volt sampling and shunt mixing.
12. Determine the voltage gain, input gain and out impedance with feedback for voltage- Series feedback having A=100, Ri=10K? and Ro=20K? for a feedback of (a) ?=0.1 and (b) ?=0.5
13. Determine the voltage gain, input gain and out impedance with feedback for Voltage-shuntfeedback having A=100, Ri=10K? and Ro=20K? for a feedback of (a) ?=0.1 and (b) ?=0.5
14. Determine the voltage gain, input gain and out impedance with feedback for Current - Series feedback having A=100, Ri=10K? and Ro=20K? for a feedback of (a) ?=0.1 and (b) ?=0.5
15. Determine the voltage gain, input gain and out impedance with feedback for Current - Shunteedback having A=100, Ri=10K? and Ro=20K? for a feedback of (a) ?=0.1 and (b) ?=0.5

Part – B

1. Give the block diagram of a general feedback amplifier. State the function of every block
2. Using illustrations, discuss the effects of negative feedback on the amplifier performance
3. (a) Identify the 4 possible topologies of a feedback network.
(b) Identify the o/p signal & f/b signal for every topology (Whether current or voltage)
(c) Identifiy the transfer gain & feedback factor for every topology.
4. Draw the block diagram of current sampling – Series Mixing feedback configuration and derive an expression for transfer gain, input resistance and output resistance.
5. Draw the block diagram of current sampling –Shunt Mixing feedback configuration and derive an expression for transfer gain, input resistance and output resistance.
6. Draw the block diagram of Voltage sampling – Series Mixing feedback configuration and derive an expression for transfer gain, input resistance and output resistance.
7. Draw the block diagram of Voltage sampling – Shunt Mixing feedback configuration and derive an expression for transfer gain, input resistance and output resistance.
8. Sketch the circuit of a single stage CC Amplifier that uses voltage sampling –Series Mixing . discuss the operation of circuit . Derive expression for Af , Rif, Rof

Earning:   Approval pending.