12058

P.T.O.

21112 3 Hours / 100 Marks Seat No.

Instructions : (1) All Questions are compulsory.

(2) Illustrate your answers with neat sketches wherever necessary.

(3) Figures to the right indicate full marks.

(4) Assume suitable data, if necessary.

(5) Use of Non-Programmable Electronic Pocket Calculator is permissible.

Marks

1. Attempt any TEN. 20

(a) State the need of biasing & list its types.

(b) List any two applications of transformer coupled Amplifier.

(c) Define & with respect to transistor.

(d) Draw pin diagram of IC 723.

(e) Define Ripple factor and Transformer utilization factor with respect to rectifier.

(f) Draw symbols of Schottky diode & point contact diode and label its terminals.

(g) Define load & line regulation with respect to regulators.

(h) State the effect of coupling & emitter bypass capacitor on bandwidth.

(i) List the types of transistor & draw their symbols.

(j) Define doping & dopants with examples.

(k) Define Rectifier & state its need.

(l) State the operating principle of Photodiode.

12058 [ 2 ]

2. Attempt any FOUR. 16

(a) Explain Thermal Runaway. How it can be avoided ?

(b) Explain the construction of NPN transistor with the help of diagram.

(c) Compare Half Wave Rectifier with Full Wave Rectifier. (Any 4 Points)

(d) State four important features of IC723. What is the use of CL & CS

terminals ?

(e) Explain V-I characteristics of P-N junction diode with the help of circuit diagram.

(f) Explain single stage CE amplifier with the help of circuit diagram.

3. Attempt any FOUR. 16

(a) Explain center-tapped full wave rectifier with the help of circuit diagram & input and output waveforms.

(b) Draw & explain voltage divider bias method.

(c) Draw two stage R-C coupled Amplifier & draw its frequency response.

(d) Explain construction & working principle of LED.

(e) Derive relation between & with respect to BJT.

(f) Construct a dual power supply capable of giving 12V using 78XX & 79XX series ICs.

4. Attempt any FOUR. 16

(a) Compare CB, CE & CC configuration on the basis of

(i) Input Impedance

(ii) Current Gain

(iii) Voltage Gain

(iv) Output Impedance

(b) Define Breakdown. Explain Avalanche Breakdown.

12058 [ 3 ]

P.T.O.

(c) Draw Hybrid equivalent circuit for a transistor & define the R-parameters for CE model.

(d) Explain the block diagram of regulated power supply & also state its need.

(e) Draw the circuit diagram of single stage CE amplifier & then draw its AC equivalent model.

(f) Draw & explain the construction of n-channel JFET.

5. Attempt any FOUR. 16

(a) Explain construction & working principle of Schottky diode.

(b) Draw V-I characteristics of UJT & explain.

(c) Calculate the Q - Point values of IC & VCE for the voltage divider bias

circuit with the values R1 = 9.1k, R2 = 4.7k, RE = 560 RC = 1k,

VCC = 10V, dc = 100.

(d) Explain shunt capacitor filter with the help of circuit diagram & waveforms.

(e) Compare RC coupled, Direct coupled & Transformer coupled Amplifiers (4 Points).

(f) Explain the formation of depletion region in P-N junction.

6. Attempt any FOUR. 16

(a) Draw the input & output characteristics of CE configuration and describe the nature in brief.

(b) Explain with the help of circuit diagram Zener diode as Voltage Regulator.

(c) Draw direct coupled amplifier. State its advantages, disadvantages & applications (2 each).

(d) Compare pn-junction diode & zener diode. (4 points)

12058 [ 4 ]

(e) Draw the circuit diagram of bridge rectifier with π filter. State the formula for ripple factor for π filter & state its dependence on load.

(f) An amplifier has a signal input voltage of 0.25V and draws 1mA from the source. The amplifier delivers 8V to load at 10mA. Determine

(i) Current gain

(ii) Voltage gain

(iii) Power gain

(iv) Input Resistance of this amplifier

___________