G. H. Raisoni College of Engineering, Nagpur Department of Electronics & Communication Engineering

LINEAR ELECTRONICS CIRCUITS QUESTION BANK

Multiple choice questions

1. A differential amplifier amplifies the ---------- between two input signals.

a) addition b) subtraction c) multiplication

2. The differential amplifier can amplify ac as well as dc signals because it

employs ----------. a) b)

3. Noise of input signal in differential amplifier a) increases b) decreases c) remains the soul

4. Cascaded differential amplifier requires level translator because of d) impedance matching e) isolating each stage f) d.c.shift.

5. In case of constant current bias ,R1 is replaced by diodes D1 & D2 TO

g) increase the input impedance h) improve thermal stability i) increase gain

6. If CMRR is high ,the wide variation of input within the tolerable limits of the

equipment makes output j) high k) low l) the same

7. For a.c analysis of differential amplifier we use m) h-parameters n) r-parameters o) none of above

8. In all types of differential amplifier DC operating point p) is not equal q) is equal r) is dependent on application

9. A single supply operational amplifier is a) LM 318 b) MC 414 c) LM 324

10. The cascode amplifier is composed of direct coupled s) CE-CB configuration t) CC-CC configuration u) CC-CB configuration

11. Input bias current is always is ________. a) greater b) equal c) less than input offset current

12. If input frequency is exceed the slew rate the output will be________.

a) distorted b) not distorted c) amplified

13. The operational amplifier can be nulled by _________. a) using an offset voltage compensating network b) using an error minimizing resistance c) cutting off the power supplies

14. Open loop configuration of operational amplifier is not need for _________.

a) linear operation b) nonlinear operation c) none of above

15. Slew rate is defined by________ a) dv/dt(max) b) di/dt(max c) none of the above

16. The slew rate has _______ a) positive temperature coefficient b) negative temperature coefficient c) none of the above

17. Operational amplifier offset voltage due to input bias circuit can be significantly

reduced if we use

a) offset compensatory network b) offset minimizing resistance

18. The standard supply voltage for an ordinary operational amplifier is _________

a) 15 volts b) 13 volts c) 12 volts

19. The input offset voltage _______ with negative feedback . a) increases b) decreases c) does not change

20. Specified value of CMRR for 741 opamp is ________. a) 30 dB b) 40 dB c) 90 dB

21. 741 opamp is a chip of type _________. a) industrial b) military c) commercial

22. voltage follower is a special case of __________. a) inverting configuration b) non-inverting configuration c) difference configuration

23. frequency response of differetiator is same as that of ______. a) high pass filter b) low pass filter c) band pass filter

24. frequency response of integrator is same as that of ______. a) high pass filter b) low pass filter c) band pass filter

25. voltage shunt configuration is nothing but ________ a) inverting configuration b) non-inverting configuration c) difference configuration

26. voltage series configuration is nothing but ________ a) inverting configuration b) non-inverting configuration c) c) difference configuration

27. the type of feedback used for closed loop configuration is _______ a) positive feedback b) negative feedback c) none of the above

28. instrumentation amplifier is used to amplify the output of __________.

a) speaker b) transducer

29. basic differentiator fails to work at ________. a) low frequency b) high frequency c) medium frequency

30. basic integrator fails to work at ________. a) low frequency b) high frequency c) medium frequency

31. In which of the following is an operational amplifier (op-amp) used?

a) oscillators b) filters c) instrumentation circuits d) all of the above

32. What is the difference output voltage of any signals applied to the input terminals?

a) the differential gain times the difference input voltage b) The common-mode gain times the common input voltage c) the sum of the differential gain times the difference input

voltage and the common-mode gain times the common input voltage

d) the difference of the differential gain times the difference input voltage and the common-mode gain times the common input voltage

33. What is the difference voltage if the inputs are an ideal in-phase signal?

a) the differential gain times twice the input signal b) the differential gain times the input signal c) the common-mode gain times twice the input

signal d) the common-mode gain times the input signal

34. The larger the value of CMRR, the closer the output voltage is to the difference input times the

difference gain with the common-mode signal being rejected

a) True b) False

35. What is the voltage gain of the unity follower?

a) 0 b) 1 c) 1

d) infinity

36. What is the scale multiplier (factor) of a basic integrator? a) R/C b) C/R c) RC d) 1/RC

37. Which of the following is (are) the result of gain reduction by a feedback?

a) The amplifier voltage gain is a more stable and precise value.

b) The input impedance of the circuit is increased over that of the op-amp alone.

c) The output impedance is reduced over that of the op-amp alone.

d) all of the above

38. third order Butterworth low pass filter has upper cut off frequency of 1KHz.The gain of the filter drops by -------- if frequency is increased to 2KHz.

a) 6db b) 18 db c) 20 db d) 60 db.

39. For an Op-amp based wien Bridge Oscillator , if the oscillations stops after a few cycles, then the cause is ---------------.

a) the amplifier gain is too high. b) The loop gain is less than 1. c) The loop gai is equal to 1. d) The loop gain is greater than 1.

OBJECTIVE QUESTIONS

1. What are the Four types of differential amplifiers ?

2. What is the figure of merit of a differential amplifier?

3. What is the swamping resistor in differential amplifier?

4. The transfer curve of opamp is the graph of ________ versus differential input voltage.

5. Input impedance of DIBO-DA is________.

6). The gain reduces in case of ________ feedback.

7)The distortion increases in case of _______ feedback.

8. The specified value for slew rate of 741 opamp is ______.

9) The specified value for open loop gain of 741 opamp is ______.

10)The level translator is to shift _______ level down to ground.

11)For emitter coupled amplifier RE-> , CMRR-> ----- 12)The second state of OP_AMP consists of dual input ------- output differential amplifier. 13)Differntial amplifier is ----------coupled amplifier As common mode gain decreases the value of CMRR ------------- 14)Current source is used as ----------element in amplifier 15)Biasing circuit provides ----------stabilization 16)Level shifter of op-amp should have ----------input impedance 17)Differntial amplifier is perfectly balanced if transistors are ----------- 18)Level shifter of op-amp shifts o/p dc level down to ------------ 19)CMRR is -----------proportional to RE 20)Offset voltage compensating network is connected in between pin number ----&----- of OPAMP 21)Output stage of opamp provides ------ o/p resistance 22)1DC voltage is well above the ground potential due to ------- coupling. 23)To overcome noise problem in level shifter ------- is used

24)O/p DC level is always -------- than input dc level 25) When same voltage is applied to both the terminals of differential amplifier, it is said to operate in ------------ configuration. 26) Summing amplifier can be converted into summer by takin all the resistors of ___ equal value. 27)The gain of voltage follower is ____.

28) Photodiode is an example of _______to________ converter. 29) ______ to_______ has application in tansmission lines. 30) The input resistance of NI configuration is given by ________-.

31)Average rate of change of offset voltage per unit time is called as ----

32)OPAMP has standard slew rate of --------- 33)CMRR has standard value for 741 IC as ---------- 34)UGB mean gain of opamp at a frequency ----------- 35)Maximum rate of change of o/p voltage is ----- 36)Ideal OPAMP has ------ voltage gain 37)For ideal opamp when i/p voltage is zero then o/p voltage is ---- 38)The ideal value of SVRR for 741 opamp is ------------ 39)Algebric difference between two i/p currents of OPAMP is -----------

40).Input two-voltage range of for 741 IC is -------------- 41).The average of two-i/p bias current is called as ----------- 42)For DIP package of Operational amplifier DIP means ----------- 43)The input bias current value for 741IC is -------- 44)The input offset current value for 741IC is ------- 45)This is the last stage of OPAMP ------------------ 46)The circuit in which output current is forced to equal input current is said to be a ------

47)What are the different types of adder circuit? 48)What do you mean by scalar adder? 49) Which type of frequency responce of integrator? 50) Which type of frequency response of differentiator? 51) What is difference between practical integrator and ideal integrator? 52)What is difference between practical differentiator and ideal differentiator? 53)What do you mean by average adder? 54)Draw the circuit diagram of subtractor 55) What is importance stability resistor? 56) What is importance of capacitor in integrator? 57) What is importance of resistor in differentiator? 58) What is the effect of noise integartig circuit? 59) What is the effect of noise differentiator circuit? 60)What are the application of integrating circuit? 61)What are the application of differentiating circuit? 62) which type of filter we get from integrator and differentiator 63)What are different application of adder circuit 64)What are different application of buffer circuit 65)What do you mean by quality factor? 66) What is the range of quality factor for band reject filter? 67)What is the range of quality factor for band pass filter? 68) What do you mean by order of filter?

69)What do you mean by roll over frequency? 70)What is the importance of higher order filter? 71) What do you mean by cut-off frequency? 72)Is it possible to design band pass filter by using one high pass and one low pass filter? 73)What is difference between active filters and passive filters? 74) What is difference between analog filters and digital filters? 75) Which filters are more useful analog or digital? 76) What are the disadvantages of analog filters? 77) What are the different steps for the designing of low pass filters? 78) What are the different steps for the designing of high pass filters? 79) What is the importance of major and minor lobes in filter response? 80)What happened if order of filter is not increased? 81)What are different application of low pass filter circuit 82)What are different application of high pass filter circuit

83) Define Oscillator &Explain Barkhausain criteria for oscillations ?

84) What are the advantages of Active filter over passive one ?

85) What is Butter worth Response?

86) What are the advantages of Higher order filters?

87) List the most commonly used filters?

88) What is an all pass filter ? Where and why it is needed?

89) How are the Oscillators Classified?

90). What is the difference between comparator & Schmitt trigger ?

91) Define Resolution, settling time, Conversion time for D/A Converter?

92) What is comparator?

93) What is Voltage limiting & why it is needed?

94) What is the difference between Clippers & Clampers?

95) What is Sample & hold Circuit? Why it is needed?

96) What is the basic difference between comparator & Schmitt trigger?

97) What is a Multiviberator circuit?

98) What is Phase Locked Loop?

100) What is the major difference between Analog & digital PLL?

101)List the applications of PLL?

102)What are the two basic modes of operation of IC 555?

103)List important features of IC 555?

104) What is a Regulator? List four different types of Regulators?

105)What is Switching Regulators?

SUBJECTIVE QUESTIONS :

1. Draw four-stage block diagram of OPAMP 2. Discuss single input unbalanced output differential amplifier 3. Why CMRR->for emitter coupled differential amplifier when RE-

> 4. Write a short note on Constant current source 5. Write a short note on current mirror 6. Write a short note on simple current source 7. Write a short note on level shifter 8. Write a short note on level shifter with potential divider 9. Write a short note on level shifter with zener diodes 10. Perform AC analysis over DIBO differential amplifier 11. Perform DC analysis over DIBO differential amplifier 12. What is offset? How it can be eliminated? 13. If differential gain of differential amplifier is 112 & input is

2sin100t V, then determine common mode output if CMRR is 55db

14. What is complementary push pull amplifier?

15. For a DIBO differential amplifier RC=2.2K,

RE=4.7K,ac=dc=100, VBE=0.7V.Calculate operating points, voltage gain & input resistance,

if VCC=12V

16. For a DIBO differential amplifier RC=2K, RE=4K,ac=dc=50, VBE=0.2V.Calculate operating points, voltage gain & input

resistance, if VCC=15V

17)Discuss overload protection circuit

18)Write a short note on frequency response 19)Write down ideal characteristics of ideal OPAMP 20)Draw ideal voltage transfer curve of 741 21)Why negative feedback is desirable in OPAMP 22)Explain virtual ground concept 23)Define CMRR, SVRR, UGB & power consumption 24)What is thermal drift? How affects performance of OPAMP 25)Define slew rate. Derive its expression. 26)Draw offset voltage compensating network 27)Draw pen loop frequency response of 741 IC 28)What is Miller effect compensation? 29)What is the difference between internal & external compensation? 30)How fast the output of OPAMP will change by 20V, if its slew rate is 1V/u sec 31)Explain in detail packages of 741 available in market 32)Explain the concept of virtual ground in detail 33)the integrators used in analog computation has three mode of operation draw the circuit for such an integrators and explain its work. 34) Discus the errors on integrators due to input bias current and in put offset voltage. 35) for the given integrators show the waveforms of out put voltage, Vo and V1 if V1 is in put voltages as shown. 36) Prove that the circuit show in figure is a non-inverting integrators with Vo=2/RC/Vidt. 37) what is the differentiator? What are their limitations? Who they are over come in practical differentiator. 38)List two demerits of differentiator using op- amp. 39) draw the circuit of simple logarithmic amplifier find the expression for its out put. 40) write a short note on multiplier. 41) write a short note on divider. 42)write a short note on differential amplifier configarations. 43)Write a short note on bridge amplifier and its type. 44) For the inverting bridge amplifier, find Vo in terms of bridge deviations bridge power supplies and resistor. 45) If is common particle to employ more than one op-amp to realize differential DC amplifier, instrumentation amplifiers a typical examples sate its two important advantages with the help of the circuit diagrams derive an expression for its gain in terms of the circuit components. 46)For the instrumentation amplifier shown in figure verify that. 47) For the circuit show, derive the expression for Vo in terms of Vs and the circuit parameters. 48)For the differential amplifier show in figure, find conduction so that common mode in put signal dose not contribute to the out put hence derive relation for differential gain. 49)Draw the circuit for full wave precision rectifier and deduce its characterstics 50)Define oscillator .State Barkhausens criteria for oscillator .How are oscillator classified ?What is frequency stability?Explain its significance 51)Write short note on phase shift oscillator

52)Draw a wein bridge oscillator circuit using op-amp.Explain its working 53)Explain how the problem of growing oscillator in a wein bridge oscillator is overcomed 54)Write short note on RMS to DC conversion 55)Write a short note on unidirectional current source and sinks. 56)Define communication filter .How are the filter classified 57) With neat sketches explain the operation of the active low pass filter. 58)State the advantages of active filters over passive filters.

Draw the circuit of second order low pass filter 59)Draw the first order high pass butterworth filter.Derive its equation 60)Ahigh pass butterworth filter is to be designed to have 3-db bandwidth of 200Hz and an attenuation of 30 db for less than 100Hz .Find the order of the filter. 61)What is the Band pass filter?How do you define the measure of selectivity of band pass filter?What are the various types of band pass filter?How do you identify the type of filter? 62) Design a phase shift oscillator to oscillate at 100 Hz. 63)For voltage to current convertor shown in figure ,determine expression for IL 64) Design wide band pass filter with Fl=400 Hz,Fh=2 Khz and passband gain 4 using op-amp 65)Using the frequency scaling technique ,convert the 1 khz cut-off frequency of low pass filter of above question to a cut-off frequency of 1.6 khz 66)What is a filter ckt ? Why it is necessary in electronics ckt? 67)Compare active filter with passive filters? 68)State advantages and limitations of active filter over passive filter. 69)Give the name of different types of filter. 70)Explain 2nd order Butterworth filter in detail. 71)Show the difference between frequency response of different order filters. 72)Explain a)Low pass active filter b) High pass active filter

c) Band pass active filter d)Band reject active filter. 73)Design a Notch filter for the notch frequency of 100 Hz. 74)Design a second order narrow band pass filter. 75)Design a band-pass active filter with center frequency of 750hz , gain of 1.5 and Q = 5. 76)State different types of oscillators. 77)Explain RC phase shift oscillator . 78)Explain wein bridge oscillator And give its two application. 79)Explain Quadrature oscillator . 80)Describe the application of oscillators and filters in analog ckt . 81)Design oscillator for generating oscillations of 1mhz and the phase shift of 360 degree. 82)Design a 2 nd order filter which allow the frequency of range 1.4khz to 90.8khz. 83)What is PLL? Explain in detail.? 84)Explain a)Lock Range b) center frequency c)capture range d) Loop gain

i. e)Free running frequency. 85)List the desirable characteristics of VCO. 86)Explain the application of IC565 as a a) FM demodulator b)freuquency multiplier 87)What do you mean by voltage regulator .Explain in detail. 88)Draw a block schematic of PLL IC NE/SE 565and describe its functions. 89)Explain different modes of operation of IC555 . 90)Draw and explain ckt diagram for monostable Multivibrator. 91)Draw and explain ckt diagram for astable Multivibrator. 92)Draw and explain ckt diagram for bistable Multivibrator. 93)Give the block diagram of IC 566 VCO and explain its operation. 94)Draw the ckt of PLL AM detector and explain its operation. 95)Discuss FSK generator using IC555 timer. 96)Draw and explain block diagram of frequency multiplier. 97)Draw and explain the ckt of scmitt trigger using Ic 555 timer.and explain its operation. 98)Design symmetrical square wave generator of 10khz. Also give its application. 99)Draw and explain characteristics of three terminal IC regulators.

100)Explain the application of IC565 as a a) FM demodulator b)freuquency multiplier

101)What do you mean by voltage regulator .Explain in detail. 102)Draw a block schematic of PLL IC NE/SE 565and describe its functions. 103)Explain different modes of operation of IC555 . 104)Draw and explain ckt diagram for monostable Multivibrator. 105)Draw and explain ckt diagram for astable Multivibrator. 106)Draw and explain ckt diagram for bistable Multivibrator. 107)Give the block diagram of IC 566 VCO and explain its operation. 108)Draw the ckt of PLL AM detector and explain its operation. 109)Discuss FSK generator using IC555 timer. 110)Draw and explain block diagram of frequency multiplier. 111)Draw and explain the ckt of scmitt trigger using Ic 555 timer.and explain its operation. 112)Design symmetrical square wave generator of 10khz. Also give its application. 113)Draw and explain characteristics of three terminal IC regulators.

114)An amplifier system has the following input and output signals

(i)What is the voltage gain of the system? (ii)Draw a circuit diagram, based on a single op-amp, for a voltage amplifier which could be used for this system. Give suitable values for any components.

115) An extract from the data sheet of an op-amp is shown in the following table.

The following diagram shows the op-amp set up as a voltage amplifier. The op-amp is powered from a 15 V power supply and saturation occurs at 12 V

a) Calculate the voltage gain of the amplifier

b) Complete the following graph to show how the output voltage VouT varies as the input voltage VIN is increased from -2 V to +2 V.

c) Calculate the bandwidth of the amplifier for this value of voltage gain

d) In response to a step input, the output voltage of the amplifier changes from -5 V to +5 V.

Calculate the time taken for this change in output voltage to occur.

116) Design a zener constant current bias circuit for the following specifications

a) emitter current Ie = 10 mA b) zener diode with Vz = 4.7 V and Iz = 53 mA c) Bac = Bdc = 100, Vbe = 0.715 V d) Supply voltge Vee = -9 V

117) Design the DIBO-DA using the diode constant current bias to meet the following specifications

a) supply voltage = 12V b) Ie = 1.5 mA and Vbe = 0.7V. c) voltage gain less than equal to 60.

118) A differential amplifier has an output voltage given by Vo = 9 V2-10 V1.

The two inputs are V1 = 10 mV and V2 = 20 mv. Determine common mode input voltage, common mode gain, the differential gain, common mode output and CMRR.

.An opamp has slew rate of 0.5 V/Us .what is the maximum frequency for which the amplifier will give an undistorted sinusoidal output signal of (a) 30Vp-p (b) 50Vp-p.

119)For inverting amplifier with following specifications find total output offset voltage due to Voi and input bias current Ib.

Rf = 100 k, R1 = 1K, Vio = 7.5mV, Ib = 250Ma

120) The opamp used as NI amplifier has following specifications, dVio/dT = 30 uV/C ,dIio/dt = 10 nA/C the amplifier is nulled at 25C and uses R1 = 100 ohms and Rf = 8.2 K ohms.If a 20 mv peak sine wave 100 Hz is applied at input.

(1) Calculate error voltage & output voltage at 45C. (2) Draw output voltage waveform at 25C & 45C.

121)Find R1 and Rf in the lossy integrator so that peak gain is 20 dB down from its peak value when w = 10000 rad/sec. Use capacitance of 0.01 uF.

122) (a) Design a differentiator to differentiate an input signal that varies frequency from 10 Hz to 1KHz.

(b) if a sine wave of 1V peak at 1000 Hz is applied to this differentiator draw its output waveform.

123) Find the expression of output Vo for differential amplifier with 3 opamps or instrumentation amplifier.

Find the value of the variable resistor such that the amplifier is supposed to offer the gain of 1300 and R4 = 10K and R1 = 10K and Rf =1M.