BSc Physics SEM VI 2016 17 2016-17 Physics II Electronics Question Paper - Mumbai University | munotes

Questions asked in this paper

• (2) Figures to the right indicate full marks

1. Q1 (a) Attempt any one:
   • (i) Sketch the cross-section of Depletion MOSFET and explain its working. 10 Draw and explain its drain and transconductance curves
   • (ii) Explain the use of SCR as half wave rectifier and derive the expressions for 10 its average output voltage and current
   • (b) Attempt any one:
   • (i) the voltage divider bias of a JFET. State and explain the condition 5 under which the drain current in a voltage divider bias is approximately constant for any JFET
   • (ii) Draw the V-I characteristics of a Triac. Explain how Triac can be used to 5 control the intensity of high power lamp?
2. Q2 (a) Attempt any one:
   • (i) Draw a neat circuit diagram of a transistorized astable multivibrator. With 10 the help of necessary waveforms, explain its working and derive an expression for its output frequency
   • (ii) With the help of a neat diagram, explain the working of a voltage regulator with a current limiting arrangement. State the expression of the shorted load
   • (b) Attempt any one:
   • (i) Explain the working of a three terminal LM 317 voltage regulator as a 5 variable voltage regulator. Derive an expression for its output voltage Gi) With the help of neat circuit diagram, explain the use of transistorized 5
3. Q3 (a) Attempt any one:
   • (i) Draw a neat circuit diagram of the basic configuration of instrumentation 10 amplifier using 3 OpAmps. Explain its working and derive an expression for its CMRR Gi) Draw neat circuit diagram and explain working of one-shot multivibrator 10 using Derive an equation of pulse width of the output wave. Sketch expected waveforms at threshold and output terminal
   • Q. P. Code : 02136
   • (b) Attempt any one:
   • (i) the circuit of first order low pass filter operated in non-inverting mode, 5 Rin=1KQ, R Calculate cutoff frequency if the filter section uses R=10 KQ and Also find pass band gain of the filter
   • (ii) Draw and explain functional Block diagram of IC555. 5
4. Q4 (a) Attempt any one:
   • (i) Draw the circuit diagram of 4 bit asynchronous Up/ Down counter. With 10 the help of relevant timing diagrams and truth table, explain its working
   • (ii) Explain the working of TTL two input NAND and NOR gates. 10
   • (b) Attempt any one:
   • G) the working of CMOS NAND gate. 5
   • (ii) Explain the working of transistorized AM modulator. 5
5. Q5 (a) Attempt any one :
   • (i) For JFET, calculate the ratio of against to obtain 4 a drain current equivalent to 30% of the maximum value of the drain current
   • (ii) Anacvoltagev = 240sin314t is applied to an SCR half wave rectifier. If 4 SCR conducts for 7.3ms in one cycle, then, find the forward breakdown voltage of SCR and the average output voltage of the rectifier
   • (b) Attempt any one :
   • (i) The Schmitt Trigger circuit using discrete components has Vcc = 12V, 4 V, KO, KO and Re=1 Find the values for the switching levels and the hysteresis voltage
   • (ii) A transistorized monostable multivibrator has output pulse with of 75 % 4 duty cycle. Its timing resistor is 33KQ and capacitor is 33 nF. Find the value of input trigger frequency and the pulse width of output pulse
   • (c) Attempt any one:
   • (i) A555 Timer connected for an astable operation, has Ri=10KQ, Ro=20 4 and C = 10 nF. Find the duty cycle and the time period of the Output pulse If Vcc = 12 Volts, then find the minimum and maximum voltage across the
   • (11) Inthe circuit of ramp generator using the potential divider 4 arrangement at base of transistor is developed with Ri= 10KQ, Ro= 10KQ ff pF and =12 V, then, calculate the slope of the ramp for
   • (d) Attempt any one:
   • G) Draw a logic diagram of mod-5 counter and write its truth table. 3
   • (ii) The antenna current of an AM transmitter is 10A when only carrier is sent. 3 It changes to 11.5A when the carrier is sinusoidally modulated. Find the percentage of modulation

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