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

Name' of the Course : B.Sc. (H) Electronics Ill (Under NEP UGCF 1. (a)Draw .and explain the circuit of a voltage follower. (3) (i) Det?rmine the Upper Threshold Voltage and the Lower Threshold Voltage.. (b) For an integrator with R = 100 kQ, C = 0.1 LtF, and = 2V Dc for 10 ms, `find vo(t). (3) (ii) Calculate the hysteresis width. (iii) Sketch the input-output characteristic curve indicating threshold points. (c) Find the value of the components to be used in a monostable multivibrator which to be used as a divide-by-2 frequency network. The frequency of the input trigger signal is 4kHz. (3) (b) Describe the working principle of an astable multivibrator. How can the duty cycle of an astable multivibrator be made 50%? •(6) (d) Explain the following parameters of Operational (i) Input Offset Voltage (ii) Supply Voltage Re`jection Ratio (e) Calculate the frequency of oscillation for a phase shift oscillator with R = 10 kQ and C = (c) What is the significance of CMRR? Given R2=R4=10 KQ, R3=R[=1KQ, Vr]-V]2=Vd=5mv Sine wave at 1 KHz, Vni=2mv at 50 Hz. Calculate the output voltage at 1 KHz. Also find the amplitude of the induced noise voltage at 50 Hz. Op-amp is 741 with CMRR=90dB. (6) 7. (a) An inverting Schmitt Trigger as shown below is implemented using an operational amplifier with the following parameters: (6) Saturation voltages V sat = 12V, Reference input VR = +2 V (f) An inverting summing amplifier has the following parameters Find its output. (3) 2. (a) The following specifications are given for dual input balanced output 6 differential amplifier- R. = 2.2 - VEE=-10V, Pac-Pai-100 and Vo=0.715 V (i) Determine Icq and Vceq (ii) Determine the voltage gain (iii) Determine input and output resistance (iv) Determine the output voltage if Vinl = 50 mV peak to peak at 1 KHz and Vinz = 50 mV peak to peak at 1 KHz. (v) What is the maximum peak to peak output voltage without clipping. (6) (b) D erive closed loop gain, input resistance, output resistance and bandwidth for non-inverting amplifier with ne.gative feedback. (6) (c) Explain the need of negative feedback in op-amp based amplifiers on the basis of the transfer characteristics. List the important characteristics of an ideal op-amp. (6) 3. (a) Why are integrators preferred over differentiat®rs in analog computation? Derive the transfer function of a basic op-amp. based. differentiator. Discuss the disadvantages of the basic differentiator and how are they improved? (b) Design a practical integrator circuit for gain limiting frequency fa =1 KHz. Draw the output voltage wave form if the input is a sine wave with a peak-to- Peak amplitude of 5 V at 2 kHz. Discuss the limitations of a basic integrator. (6) (c) What are active filters? What do you understand by the order of an active filter? Draw the magnitude response of Band Pass Filter, Band Rej,ect Filter and All Pass Filter. Design a first order Butterworth LPF of gain 4 and cut off frequency of 5 KHz. (6)