BSc Sem VI 2022 2023 Apr 2023 PHYSICS ELECTRONICS Question Paper - Mumbai University | munotes

Questions asked in this paper

• 2. Figures to the right indicate full marks

1. Q1 Attempt any two
   • (i) Explain various methods of biasing JFET in active region. 10 Explain the construction and working of depletion mode MOSFET. Draw and discuss its drain and transfer characteristics Explain the use of SCR as a half wave rectifier and derive the 10 expressions for its average output voltage and current
   • (iv) Explain the construction and working of a UJT. Draw the V-I 10 characteristics and explain it
2. Q2 Attempt any two
   • (i) Draw a circuit of an emitter coupled differential amplifier having 10 double ended input and single ended output. Using AC analysis derive an expression for voltage gain and input impedance Gi) Ina differential amplifier explain what is meant by common mode 10 signal. Using ac analysis derive an expression for common mode gain
   • (iii) With the help of a neat circuit diagram explain the working of an 10 inverting Schmitt trigger using operational amplifier. Derive an expression for its feedback factor and hysteresis. Draw a neat circuit diagram of a non-inverting Schmitt trigger using operational amplifier Explain with the help of neat circuit diagram, the principle and working of Wien bridge oscillator using operational amplifier. State the expression for its frequency of oscillation
3. Q3 Attempt any two
   • (i) Draw the circuit diagram of voltage controlled oscillator using IC 555 Discuss its working. Derive the expressions for output time period
   • (i) the circuit diagram of astable multivibrator using transistors. 10 Explain its working. Sketch the waveforms at both collectors and both
   • (iii) What is a bistable multivibrator? Draw the circuit diagram of bistable 10 multivibrator using transistors. Discuss its working. What is the relation between input and output frequency of a bistable multivibrator
   • (iv) the diagram of voltage feedback regulator circuit. Explain its 10 working. Derive the expression for power dissipation in pass
4. Q4 Attempt any two
   • (i) Explain the working of a two — input Transistor Transistor Logic 10 Explain CMOS characteristics in terms of Sinking, Floating Inputs and Explain Basic Pulse Code Modulation. Explain companding process 10 used to overcome problems of distortion and noise in the transmission of audio signals
   • (iv) benefits of digital communication. 10
5. Q5 Attempt any four
   • (i) The data sheet of a JFET gives the following information: 05 Ipss = 3 MA, = -6 V and = 5000 wS. Determine the transconductance for Vgs = -4V and find drain current Ip at this point Gi) voltage v= 240sin314t is applied to an SCR half wave rectifier. 05 If SCR the forward breakdown voltage of 180 V, find the time, during which SCR remains off In oscillator circuit using operational amplifier the timing components are R=4.7 kQ and C = 0.1 uf. The feedback to non inverting terminal is applied by a potential divider with = 5 kQ and Ro = 5 kQ such that voltage across is the feedback voltage. Find the period of the output waveform
   • 2.2 kQ and C = 0.047uF. What is the cut-off frequency?
   • (v) Calculate the time period of oscillation of an astable multivibrator 05 Also calculate frequency of oscillation and duty cycle
   • (vi) A voltage feedback regulator with fold back current limiting uses 05
   • 0.7V and Calculate shorted load current and maximum
   • (vii) A TTL circuit drives an LED. When the TTL output is high, the LED 05 is dark. When the TTL output is low, the LED lights up. If the LED voltage drop is 1.75 V, Calculate LED current for a low TTL output
   • (viii) The input voltage of a compander with a maximum voltage range of 05
   • 1.2 V of 255 is 0.25V. What are the output voltage and gain?

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