SRM University 2007 B.Tech Information Technology ELECTRONIC DEVICES AND CIRCUITS - Question Paper

33. What are the disadvantages of a zero crossing detector?
34. What is the function of a Schmitt trigger?
35. List the merits of a regenerative comparator.
36. Draw the circuit diagram of an opamp based Schmitt trigger.
37. Draw the input output waveforms of a Schmitt trigger. Also draw the hysterisis plot.
38. Define upper threshold voltage and lower threshold voltage in schmitt.trigger.
39. Explain how the disadvantage of zero crossing detector is avoided in Schmitt trigger.
40. What is dead band in Schmitt trigger? Write down the expression for dead band.
41. List a few of the non-linear applications of an opamp.
42. List a few of the linear applications of an opamp.
43. What is linear opamp circuit?
44. What is non-linear opamp circuit?






TEN MARKS


1. Draw the circuit diagram of an opamp based phase shift oscillator. Sketch the circuit waveforms and briefly discuss the oscillator operation.
2. Write the oscillating frequency formula for an opamp based phase shift oscillator. explain the phase shift network attenuation and the amplifier gain requirements.
3. Write the oscillating frequency formula for BJT phase shift oscillator. explain the phase shift network attenuation and the amplifier gain requirements.
4. Draw the circuit diagram of an opamp wein bridge oscillator. Sketch the oscillator waveforms and discuss the circuit operation with necessary equations.
5. With a neat circuit diagram and necessary waveforms discuss the operation of inverting comparator.
6. With a neat circuit diagram and necessary waveforms discuss the operation of non-inverting comparator
7. Explain the working of zero crossing detector with associated circuits and waveforms. explain the disadvantage of the identical.
8. Describe the operation of Schmitt trigger with necessary waveforms and circuits. explain the advantage of Schmitt trigger over Zero crossing detector.





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UNIT V
TWO MARKS
1. List a few features of IC 555 timer.
2. What is the difference ranging from oscillator and multivibrator?
3. List a few applications of IC 555 timer.
4. What is the maximum timing range of a single IC 555 timer?
5. List the modes of operation of IC 555 timer.
6. Draw the Functional block diagram of IC 555 timer.
7. What is free running mode of multivibrator?
8. What is monostable or 1 shot multivibrator?
9. Draw the pin details of DIP IC 555 timer.
10. Draw the pin details of metal can IC 555 timer.
11. What is the function of upper comparator in a IC 555 timer.
12. What is the function of discharge transistor in IC 555 timer?
13. How IC 555 timer can support floating loads as well as grounded loads? discuss.
14. What is the function of reset pin in IC 555 timer?
15. What is the function of control voltage terminal in IC 555 timer?
16. What is the function of Discharge terminal in IC 555 timer?
17. Draw the schematic of 555 based astable multivibrator.
18. Draw the schematic of 555 based monostable multivibrator.
19. Define duty cycle D for IC 555 timer in Astable mode.
20. List a few applications of IC 555 timer in astable mode of operation.
21. Write the expression for free running frequency of oscillation of IC 555 timer.
22. Explain how you will increase the duty cycle in free running mode of IC 555 timer.
23. Draw the schematic of 555 based astable multivibrator with increased duty cycle.
24. What is a counter timer?
25. What is programmable counter timer?
26. Draw the functional block diagram of programmable timer/counter XR 2240.
27. Show how the outputs can be programmed in IC XR 2240.
28. List a few of the applications of timers/counters.
29. What is frequency divider?
30. What is missing pulse detector?

TEN MARKS
1. define in detail the function of Discharge, trigger and threshold terminal in IC
555 timer with necessary diagrams.
2. discuss the kinds of power on time delay that may be produced using IC 555 timer
with necessary waveforms and circuit diagram.
3. (i) Draw the functional block diagram of IC 555 timer and discuss.
(ii) Draw the pin diagram of IC 555 timer and briefly discuss the functions of every
pins.
4. discuss the astable mode of operation of IC 555 timer and derive an expression for
free running frequency of oscillation.
5. define with neat diagrams how duty cycle in astable mode of operation can be
increased.
6. discuss the mono stable mode of operation of IC 555 timer with neat circuit
diagram.
7. explain in detail the voltage controlled frequency shifter using IC 555 timer.
8. explain in detail any 2 application of IC 555 timer as mono stable multivibrator.
9. Show the functional block diagram of XR 2240 programmable timer/counter and
discuss its operation as counter with necessary diagrams.
10. (i) discuss the operation of frequency synthesizer with a neat circuit.
(ii) Write short notes on switch programmable timer.
11. (i) discuss how outputs can be programmed in XR 2240.
(ii) explain the application of XR 2240 as programmable timer in monostable
operation.

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Earning:   Approval pending.