[This qnestion paper comtaing 8 printed pages] Sr. No. of Question Paper Unique Paper Code Name of the Paper Name of the Course Semester Duration ; 3 Hours Instru Your roll Ne Stik it 32221403 Analog Systems and Applications BSc. (Ilons.) Physics-CBCS IV Maximum Marks : 75 ns for Candidates 1. Write your Roll No, on the top immediately on receipt of this question paper. 2. Attempt five questions in all. 3. Question No. I is compulsory. 4, Use of scientific calculators is allowed. P.T.O.3118 2 1, Attempt any five of the following : (543=15) (a) State Jaw of mass action. A silicon sample is doped with 5 x 1072 cm’. Find the concentration of electrons and holes in the sample. Given n,=2* 10? cm-3, (b) What is ‘Early’ effect in transistor? Draw the input characteristics of an n-p-n transistor in a common-emitter (CE) configuration. (c) Draw the I-V characteristics of a Solar cell for different intensities of light. (d) Draw the output characteristics of a transistor in CE mode and identify the active, cut off and Saturation regions.Sts 3 (e) What are the roles of DC toad Jine and Q-point? Where should be the location of operating point for designing an amplifier? (ft) Draw the frequency response curve of a practical op-amp differentiator circuit. (g) Establish the relation 1,-a/(1-a) 1,t/(1-@) ley where the symbols have their usual meaning. 2. (a) Explain the formation of depletion layer in pn junction diode. Derive an expression for the electric field and potential in pn junction diode. Show the variations of electric ficld and potential in pn junction diode. (10) P.T.O.4 3118 (b) For the zener diode circuit show below, determine (i) V, (across Ry). (ii) Vp (across R), (iii) 1, and (iv) P,. (5) x =| V, e200 q2Ka) Vay Pigg 830 3. (a) Explain the working of a full wave bridge rectifier using suitable diagrams and obtain the expressions for (i) ripple factor and (ii) tectification efficiency. ao)3118 5 (b) In a centre tapped full wave rectifier, the load resistance Ry" IKQ. Each diode has a forward dynamic resistance r, of 109, The voltage across half the secondary winding is 220 sin 3141. Find (a) peak value of current (b) the de or average value of current (c) the rms value of current (d) the ripple factor. 6) 4. (a) Using ‘h’ parameters, obtain expressions for current gain, voltage gain, input impedance and output impedance for transistor in CE configuration. (10) {b) Plot the output characteristics of a transistor in CB configuration and indicate the various regions of operation on it. Also explain the shape of the characteristics thus obtained. (5) P.T.O.3118 6 5, (a) What factors affect the bias stability of a transistor? Obtain the general expression for stability factor of common emitter configeraucs. Quantitatively show that the emitter resistance improves the stabilizy of the fixed bias cirs ae (b) In a Colpitt’s oscillator C, = 0.1 HF, C2 = 0.01 uF and L = $0 ma, find the frequency of oscillation. (6) 6. (a) Draw the circuit diagram of an RC phase shitt oscillator using transistor and state the Barkhausen criterion for sustained oscillations. Derive an expression for its frequency. (de) (b) Three amplifier stages are working in cascade with 0.0SV peak to peak input providing 150 V peak to sage peak output. If the voltage gain of the first stMater : 7 Sts is 20 and input to the third Slape is 15 Vv peak to peak, determine (i) The overall voltage gain (ii) Voltage gain of 204 and 34 stages, Gii) Input Voltage of the 274 stage, (5) 7. (a) Describe the working of an Op-amp based integrator and hence design a Practical Op-amp integrator to integrate an input signal that varies in the frequency tange of | KHz to 15 KHz. do) (b) Calculate the output voltage for an Op-amp based inverting summing amplifier for the following sets of voltages and resistors with Re = 1 MQ for both the cases @ V, = 1V, V, = 2V and V, = 3V, R, = 500 KQ, R, = 1 MQ and Ry ~ 1 MQ P.T.O.3118 8 Gi) V1 = -2V, V, = 3V and V, = IV, R, = 200 KQ, R, = 500 KO and R, = 1 MQ (3