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Code No: 07A40402 R07 Set No. 2

II B.Tech II Semester Supplementary Examinations,May 2010LINEAR IC APPLICATIONS

Electronics And Instrumentation EngineeringTime: 3 hours Max Marks: 80

Answer any FIVE QuestionsAll Questions carry equal marks

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1. Write short notes on:

(a) Frequency of oscillation of a square wave generator

(b) Triangular wave generator using a square wave generator. [8×2]

2. (a) Explain the difference between the DC and AC voltage follower.

(b) if a 741 IC is configured as an I-to-V converter, what is the lowest value ofcurrent that may be measured.

(c) Explain the difference between inverting and non - inverting amplifiers. [6+3+7]

3. (a) What are the different types of multiplexers? Explain logic diagram and truthtable of Dual 4 to 1 line multiplexer.

(b) Explain the operation of balanced modulator using neat sketch. [10+6]

4. (a) For the all pass filter, determine the phase shift φ between the input and outputat f = 2kHz. To obtain a positive phase shift what modifications are necessary inthe circuit?

(b) Derive the expression for the transfer function of 2nd order High pass filter.[8+8]

5. Explain an application in which the 555 timer can be used as Astable multivibrator.[16]

6. (a) In the circuit of figure 6, R1=100ohms, Rf=4.7kΩ , CMRR=90dB. If theamplitude of the induced 60 Hz noise at the output is 5mv (rms), calculatethe amplitude of the common mode input voltage Vcm .

(b) With neat block diagram explain the function of various building blocks of anop - amp. [8+8]

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II B.TECH II SEM–REGULAR/SUPPLEMENTARY EXAMINATIONS MAY - 2010

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Figure 6

7. (a) Explain how large open circuit voltage gain of an op - amp can be obtainedby using cascading of differential amplifier stages.

(b) Explain ac analysis of differential amplifier. [8+8]

8. (a) Explain the operation of an op - amp based weighted resistor Digital to Analogconverter through a neat circuit diagram

(b) Design a 4 - bit weighted resistor DAC whose full-scale output voltage is 10volts. Assume Rf = 10 kΩ and logic ‘1’ level as +5 volts and also logic ‘0’level as 0 volts. What is the output voltage when the input is 1011? [8+8]

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1. Write short notes on:

(a) Frequency of oscillation of a square wave generator

(b) Voltage to frequency converter. [8×2]

2. (a) Explain the operation of Monostable multivibrator using 555 timer. Derivethe expression of time delay of a Monostable multivibrator using 555 timer.

(b) Design monostable multivibrator using 555 timer to produce a pulse width of100 m sec. [10+6]

3. (a) Draw the wide band reject filter circuit and also the frequency response of it.

(b) Draw the schematic diagram of an all pass filter and determine the phase shiftφ between the input and output at f = 2kHz. [8+8]

4. (a) Why is it necessary to use an external offset voltage compensating networkwith practical op - amp circuits.

(b) Compare and contrast an ideal op - amp and practical op - amp.

(c) Explain the precautions that can be taken to minimize the effect of noise onan op - amp circuit.

(d) Calculate the effect of variation in power supply voltages on the output-offsetvoltage for an inverting amplifier circuit. [3+5+5+3]

5. (a) A non - inverting amplifier with a gain of 100 is nulled at 250C. What willhappen to the output voltage if the temperature rises to 550C for an offsetvoltage drift of 0.15mV/0C.

(b) For the non - inverting amplifier R1 = 1kΩ and Rf = 10kΩ.

i. Calculate the maximum output offset voltage due to Vos and IB. The op- amp is LM 307 with Vos = 10 mV and IB = 300nA, Ios = 50 nA.

ii. Calculate the value of Rcomp needed to reduce the effect of IB.

iii. Calculate the maximum output offset voltage if Rcomp as calculated in (ii)is connected in the circuit. [6+10]

6. (a) Find V0 for the circuit shown in figure 6

(b) Find R1 and Rf in the practical integrator (lossy integrator), so that the peakgain is 20 dB and the gain is 3 dB down from its peak when ω = 10,000rad/sec. Use a capacitance of 0.01µF. [8+8]

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Figure 6

7. (a) What are the different types of multiplexers? Explain logic diagram of Dual8 to 1 line multiplexer.

(b) Draw and explain the basic circuit for sample and hold circuit. [10+6]

8. (a) Sketch and explain the transfer characteristic of a DAC with necessary equa-tions.

(b) LSB of a 9 - bit DAC is represented by 19.6mv. If an input of 9 zero bits isrepresented by 0 volts.

i. Find the output of the DAC for an input 10110 1101 and 01101 1011.

ii. What is the Full scale reading (FSR) of this DAC? [8+8]

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1. (a) Compare and contrast an ideal operational amplifier and practical operationalamplifier.

(b) Give the design procedure of a compensating network for an op - amp thatuses ± 10 V supply voltages. Assume necessary data. [8+8]

2. (a) Draw the circuit of a Weighted resistor DAC and obtain expression for n -bits.

(b) Sketch the analog output voltage for the given digital input code.

(c) What are the major disadvantages in this type? [8+4+4]

3. (a) Describe the principle of operation of precision half wave rectifier with wave-forms.

(b) Explain the operation of voltage to frequency converter using op - amp. [8+8]

4. (a) Discuss the differences between the differential amplifiers used in the first twostages of op - amp.

(b) Compare and contrast an ideal op - amp and practical op - amp.

(c) Draw an ideal voltage transfer curve of an op - amp. [8+5+3]

5. (a) For the non - inverting a.c. amplifier Rin = 50Ω, ci = 0.1µf, R1 = 1KΩ,R0

= R3 = 820Ω, RF = 5.6KΩ and Rl = 10KΩ. Determine the gain and bandwidth of the amplifier.

(b) What is an instrumentation amplifier? List any three applications of theinstrumentation amplifier. [8+8]

6. (a) Define Bessel, Butterworth and Chebysher filters, and compare their frequencyresponse.

(b) Sketch the circuit diagram of band elimination filter and design a wide band-reject having fH=200Hz and fL=1KHz. Assume necessary data. [8+8]

7. Draw the functional block diagram of 555 IC timer. Explain the function of eachblock so also explain how it can be used as monostable multivibrator. Draw thecircuit and explain its operation with neat relevant waveforms and derive the pulsewidth. [16]

8. (a) Give different types of analog switches and explain them.

(b) What is multiplexer? Draw the logic diagram of 8 to 1 line multiplexer.[6+10]

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1. (a) Draw square wave generator using op - amp and explain its operation.

(b) Explain about any two linear and non - linear applications of op - amp. [8+8]

2. (a) What is an op-amp? Why it is called so?

(b) Explain the parameters that should be considered for ac and dc applicationsof an op-amp.

(c) Draw and explain the three open loop op - amp configurations with neat circuitdiagram. [4+7+5]

3. (a) Draw the circuit diagram of R - 2R ladder type D/A converter and derive theoutput expression.

(b) Mention the advantages of R - 2R ladder type compared to binary weightedtype.

(c) Find the equivalent of analog signal for digital signal of 1001 1101. [8+6+2]

4. (a) Explain how phase locked loop is used as a frequency translator and AMdemodulator.

(b) Explain linear ramp generation using 555 timer. [8+8]

5. (a) What is a switching regulator? Draw the block diagram of a typical switchingregulator and explain its operation.

(b) What are the four types of voltage regulators? Compare the performance ofthese regulators. [8+8]

6. (a) In an integrator circuit, Ri = 10Kohms, CF = 1 second, and the input is astep input Vin = 2V for 0 ≤ t ≤4. Determine the output voltage and sketchit.

(b) Draw the frequency response curve of a differentiator. How is it modified whena small resistor is connected in series with the capacitor? [8+8]

7. (a) List the conditions for oscillation in all the three types of oscillators, namely,RC phase shift, Wien - bridge and quadrature oscillators.

(b) Design an op - amp based relaxation oscillator and derive the frequency ofoscillation. [8+8]

8. For the cascaded differential amplifier shown in figure 8

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R1CF = 1second , and the input is a

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(a) Perform the dc analysis and

(b) Calculate the overall voltage gain. Assume hfe = 100, VBE = VD = 0.7V.[16]

Figure 8

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07a40402-linearicapplications

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