MADANAPALLE INSTITUTE OF TECHNOLOGY & SCIENCE III B.Tech I Semester First Mid-Term Examinations: SEP 2015

LICA (Descriptive Exam) ECE(A,C,&D)

Date: 11/09/2015 (FN) Time: 90 min Max.Marks:30

1. Write short notes on : (a) Level Translator [5m]

Working principle and types -2m Calculation of shift in dc level of each network- 3m

(b) What is the voltage at Point A and Point B for the circuit shown in below figure below if V1= 5V and V2= 5.1V .

Formula-1m Output voltage of first stage -2m Output voltage of second stage-2m

2. (a) Write Ideal Characteristics of an op-amp? The CMRR of an op-amp is 10000. Two sets of signals are applied to it. First set is V1 = +20 μV and V2 = −20 μV and the second set is V1= 540 μV and V2 = 500 μV. Calculate the percentage difference in output voltage for the two sets of signal. (5M) Ideal characteristics of op-amp-2m Formula-1m Solving problem-2m (b) Briefly explain why negative feedback is desirable in amplifier applications and derive the output voltage expression for ideal inverting amplifier? Importance of negative feedback-2m Derivation of output voltage expression-3m 3. (a) draw the equivalent circuit of an op-amp and discuss about Op-amp stability? (5M) Equivalent circuit of op-amp-2m Op-amp stability-3m (b) Define slew rate and derive the expression for it. List the causes of slew rate. (5M) Slew rate and its expression-3m Causes of slewrate-2m

4. (a) Explain ideal differentiator circuit and obtain output voltage expression? (5M) Differentiator circuit-2m Output voltage expression-3m (b) Deign an practical differentiator circuit with input signal frequency 5 kHz? Assume necessary parameters? (5M) Formula-2m Designing of differentiator-3m 5. (a) Draw the schematic of 3 Op-amp Instrumentation amplifier and derive output voltage expression?(5M) Circuit of instrumentation amplifier-2m Derivation-3m (b)Draw the circuit of three input inverting type summing amplifier and derive the expression for output voltage. (5M) Circuit of summing amplifier-2m Derivation of Vo -3m

MADANAPALLE INSTITUTE OF TECHNOLOGY AND SCIENCE,MADANAPALLE II- MID EXAM

Subject : LICA Marks : 20 Branch: ECE (A,C and D) Duration: 90 Min Year : III B.Tech, I-Sem Date://2015() Answer any Three Questions

1. a). Explain the operation of triangular wave generator using a comparator and integrator and derive the expression to calculate frequency of triangular wave form? (5m) Circuit-1m Operation-2m Calculation of f0-2m b).Design an triangular wave generator using a comparator and integrator to oscillate at 4khz,Vo(p-p)=7v Use an op-amp with + 15 V and -15 V power supply. Make necessary assumptions. (5m) Formula-2m Design and solution-3m

2. a) Explain the circuit of inverting Schmitt trigger in detail and sketch hysteresis loop?(5m) Circuit-1m Operation-2m Hysteresis loop-2m b)A Schmitt trigger with the upper threshold level VUT=0V and hysteresis width VH=0.2V converts a 1KHZ sine wave of amplitude 4VPP into a square wave. Calculate the time duration of the negative and positive portion of the output wave form.(5m) Formula-1m Designing-4

3. a).Discuss about RC phase shift oscillator and derive its frequency of oscillations f0.

Circuit-1m Derivation of f0-4m

b).Discuss about notch filter and its operation? Circuit-1m Explanation-2m Formulae-2m

4. a).Explain the operation of astable multivibrator using 555 timer and derive the expression

For duty cycle.(5m) Circuit-1m Operation-2m Expression of duty cycle-2m

b).Design an astable multivibrator circuit to generate 50% duty cycle assume necessary assumptions. Formulae-2m Designing-3m

4. a) Explain the circuit of dual slope ADC and derive expression for Va? Circuit-1m Operation-2m Expression of Va-2m

b).Explain R-2R ladder type DAC in detail? Circuit-1m Operation-2m Formulae-2m