Analog Electronics-I — DU B. Sc. (Hons) Electronics Previous Year Question Papers

2. There are seven question in all, out of which you have to attempt five questions. Q1 (a) What is an ideal diode? Explain its piecewise linear equivalent circuit. (b) What are the advantages of negative feedback in amplifiers? (c) Explain the structure of an n-channel MOSFET. (d) Explain the working principle of a shunt capacitor filter in a power supply circuit. (e) Detine the PIV rating of a diode? Compare the PIV rating of diodes used in half wave and full wave rectifier circuits. (f) Given that adc=0.985, determiné the corresponding value of Bac. Q2 (a) Draw and explain the VI characteristics of a Zener diode. How is a Zener diode used as a voltage regulator? (b) What are clamping circuits? Describe the various types of clamping circuits with the help of corresponding waveforms. (c) Explain the working of a Half wave rectifier circuit and derive an expression for its ripple factor. Q3 (a) Describe the working of a Class A power amplifier with a circuit diagram. alculațe the Efficiency. How can its efficiency be improved furth ) Determine the do bias voltage Vce and the current Ic for the voltage-divid configuration, when Vc=22V, R1=39 KS, R2=3.9 KS, Rc=10 KS, Re=1.5 KS, and B=140. Explain working of the R-C Phase shift oscillator. Derive the expressions for the Frequeney of Oscillation. Identify the active, cut off and saturation regions .of a transistor in CE mode. Define the current gains ,alpha and beta and derive the relation between them. Draw circuit diagram of cE transistor amplifier circuit. Explain its operation and • the impact of coupling and parasitic capacitances on the frequency response. Compare depledon-mode and enhancement-mode MOSFETs. Discuss the significance of the MOSFET as a switch in digital circuits. What are its advantages over BJTs? What is channel length modulation in a MOSFET? How does it affect the device's output ch aracteri stics? for a given n-MOSFET, threshold voltage, Vth=1 V, VDs=5 V, Kn'=200 HA/V2, W/L=10. When a gate to source voltage (Vgs) of 3V is applied, find the region of operation of n-MOSFET. Also, calculate the drain current IDs. Explain the operation of a common-source MOSFET amplifier and draw its small signal equivalent model. Describe the frequency response of a MOSFET amplifier. Explain the working of a CMOS inverter circuit. How does it function as a digital logic inverter? Derive the voltage gain expression for a common-source MOSFET amplifier with ' and without source. degeneration. Discuss the fundanental differences between the operation principles of MOSFETs and BJTs. Explain how these differences influence their current control mechanisms and input impedance characteristics. What causes short-channel effects in.MOSFETs, and how do they impact device behaviour as transistor sizes shrink.