Analog Electronics

(b) A single stage amplifier has a gain of 60. The collector load R_C = 500  and the input impedance is 1 K, calculate the overall voltage gain when two stages are cascaded through RC coupling,

(c) How many types of biasing are done on a BJT to work properly as an amplifier? Which one is the best and why?

(a) Show that an ideal low pass filter is non-causal system.

(b) The frequency response of a causal LTI discrete time system is given by    Find group delay and  . Discuss the type of system.

(b) Show that 

(a) Show that if 

(b) Consider the sequence x(n)=    

(i) Sketch x(n).

(ii) Find the Fourier coefficient c_k of x(n).

(a) Draw the cascade of a common cmitter stage and common collector stage and give the expression for input resistance and current gain of the circuit. 

(b) What is Darlington pair? Derive an expression for current gain in Darlington pair.

(a) Derive expression for voltage gain, current gain, input resistance and output resistance of a common base Si transistor circuit using h parameters. 

(b) Explain how phase reversal of the signal takes place when it is amplified by a single stage CE voltage amplifier?

(a) A Si transistor has a potential divider biasing. If it operates at l_c =3mA and V_CE =10V. find V_OC, R_BI, V_B and R_E for =100. Assume V_BE = 0.7 V, R_B2 = 20   and R_C = 5  

(b) Discuss IC voltage regulators.

(a) Discuss Butter worth and Chebyshev filters.

(b) Write a short note on HPFs and LPFS.

(a) Discuss wide band pass filter along with its frequency response curve.Also, discuss its frequency.

(b) Discuss the working of a log-amplifier with a suitable diagram, which provides saturation current and temperature compensation.

(a) Explain the working of a complementary symmetry class-B push pull amplifier. Show that its maximum conversion efficiency is 78.5%. What will be the conversion efficiency when power dissipation is maximum.

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(b) What is the significance of stability factor? Define and 

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(j) What are the drawbacks of complementary symmetry push pull class B power amplifier. 

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(i) What advantages does the transformer provide in a transformer coupled power amplifier? 

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(h) How does negative feedback increases bandwidth of an amplifier?

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(g) What is negative resistance region in UJT? Explain its physical significance. 

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(f) Why FET is called a voltage controlled device?

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(e) Define "current controlled device" and voltage controlled device".

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(d) Why the channel of a JFET is never completely closed at the drain end?

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(c) Explain the function of coupling capacitor and bypass capacitor.

(b) Explain Clipping and Clamping circuit with suitable examples.

Q1 Attempt all the questions:

(a) What is emitter follower? Explain.

(b) When the input to an LTI system is   and system response is  . Find the impulse response h(n) of the system and check its stability. 

(a)  is the system function of the LTI system. Specify the ROC of H(z) & unit impulse response of h(n) for the following condition:-

(i) Stable system (ii) Casual system (iii) Anti-causal system.

(b) The output y(t) of a continuous-time LTI system is found to  2e^-3tu(t) when the input x(t) is u(t).

    (i) Find the impulse response h(t) of the system.

    (ii) Find the output y(t) when the input x(t) is e^-tu(t)

(a) Find the inverse Laplace transform 

(b) Consider the analog signal x(t) = 3 cos 100 

(i) Determine the minimum sampling rate required to avoid aliasing.

(ii) If the signal is sampled at the rate fs=200Hz. What is the discrete time signal obtained after sampling?

(a) Discuss sampling and reconstruction of a continuous time domain signal x(t). 

(a) Design an OPAMP as a buffer amplifier and voltage multiplier.

(b) Explain the following:

(i) Active Loads

(a) Discuss power dissipations in transistors.

(b) Calculate the frequency of oscillations of a Colpitts oscillator with C1 - C2 = 400 pF and L= 2 mH. 

(a) Discuss principle and working of Sawtooth Waveforms Generators.

(b) Explain the working of an op-amp square wave generator. Derive an expression for the frequency of oscillation. What is the maximum amplitude of the square wave and how can it be varied? 

(a) Draw the circuit of crystal oscillator and explain its operation.

(b) Explain the following:

(iv) Voltage to Current converters

(b) Explain the following:

(iii) Current Mirrors

(b) Explain the following:

(ii) Virtual'Ground

(a) A differential amplifier has an open circuit gain of 100. The input signals are 3.25 V and 3.15 V. Determine the output voltage. What conclusion do you draw from this calculation? 

(b) The input to the differential OPAMP is a sinusoidal voltage of peak value 5 mV and frequency 2 kHz. Find the output if R = 100 ks and C=1 .

(a) Discuss op-amp as an integrator giving its applications. A 5 mV, 1 kHz sinusoidal signal is applied to the input of an op-amp integrator for which R=100 , and C =11. Find the output voltage.

(e) Explain second order low pass filter with a suitable diagram.

(d) Discuss Class C and AB amplifiers.

(c) Calculate the period of oscillations of Hertley oscillator having L1 = 1mH, L2 = 2 mH and C =0.1 

(b) Explain circuit diagram and working of Colpitt's oscillator. Also mention the frequency of oscillations.