DRK COLLEGE OF ENGINEERING & TECHNOLOGY,
BOWRAMPET, QUTHUBULLAPUR(M), HYDERABAD-500043
ELECTRONICS & COMMUNICATIONS ENGINEERING DEPARTMENT
ASSIGNMENT QUESTION BANK
SUBJECT: PDC CLASS: II/IV B.Tech(ECE)
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UNIT-5
Q1. Design a sweep circuit using UJT with η =0.5. The sweep amplitude is to be 10v, the
sweep duration is 1msec and sweep-speed error is 10%. Select suitable values of
VBB, Vyy, R and C. Estimate the recovery time.
Q2. Compare the diode controlled and RC controlled astable blocking oscillator.
Q3. What are the advantages of RC controlled oscillator?
Q4. List the applications of blocking oscillators.
Q5. Explain : Slope speed error, displacement error and Transmission error.
Q6. Explain the working of a transistor current time base generator with the help of a neat
circuit.
Q7. Write applications of time-base circuits. With reference to time base circuits, define:
Flyback time and Transmission error.
Q8. What is meant by triggered sweep? What are the merits and demerits of triggered
sweep circuits?
Q9. Explain the method of pulse synchronisation of relaxation devices, with examples.
Q10. Define the terms: slope or sweep speed error and Displacement error.
Q11. An exponential sweep results when a capacitor is charged from a supply voltage V
through a resistor R. If the peak sweep voltage is VS , derive an expression for slope
error es.
Q12. Explain the principle of working if miller sweep circuit. Derive the expression for
sweep speed by taking miller integrator circuit.
Q13. Draw the simple single stage transistor miler integration circuit and explain how it
behaves as a time-base circuit.
Q14. Explain the operation of free running blocking oscillator ( diode controlled) with neat
sketches of current and voltage waveforms. Derive the expression for period and
duty cycle of oscillations.
Q15. How are linearly varying current waveforms generated?
Q16. What is linear time base generator? Give its applications.
Q17. Write the differences between the voltage and current time base generators.
Q18. What is a relaxation oscillator? Name some negative resistance devices used as
relaxation oscillators and give its applications.
Q19. With the help of a circuit diagram and waveforms, explain the working of a transistor
miller time base generator.
Q20. What is relaxation oscillator? Name some negative resistance devices used as
relaxation oscillators and give its applications.
Q21. Explain how UJT is used for sweep circuit.
Q22. Explain how linearity is obtained by adjusting the driving waveform of current sweep
circuit.
Q23. Derive the relationship between the slope, transmission errors.
Q24. With the help of a circuit diagram and waveforms, explain the working of a transistor
bootstrap time base generator.
UNIT-6
Q1. Explain the principle of “synchronization” and “synchronization with frequency
division”
Q2. Explain the method of pulse synchronization of relaxation devices, with examples.
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Q3. A UJT sweep operates with VV = 3V, VP = 16V and η=0.5. A sinusoidal synchronizing
voltage of 2V peak is applied between bases and the natural frequency of the sweep
is 1KHz. Over what range of sync signal frequency will the sweep remain in 1:1
synchronism with the sync signal.
Q4. Compare sine wave synchronization with pulse synchronization.
Q5. With the help of a circuit and waveforms, explain the frequency division by an astable
multivibrator.
Q6. The relaxation oscillator, when running freely, generates an output signal of peakpeak amplitude of 100V and frequency 1KHz. Synchronizing pulses are applied of
such amplitude that at each pulse the break down voltage is lowered by 20V. Over
what frequency range may the sync pulse frequency be varied if 1:1 synchronization
is to result? If 5:1 synchronization is to be obtained ( fP/fS=5), over what range of
frequency may the pulse source be varied?
Q7. explain the frequency division by an astable blocking oscillator.
Q8. Compare sine wave synchronization with pulse synchronization.
Q9. Explain how an astable multivibrator is used as frequency divider.
Q10. Explain the operation of a monostable multi used as frequency divider.
Q11. Why synchronization is needed in digital systems?
Q12. Draw and explain the block diagram of frequency divider.
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UNIT-7
Q1. Derive the expressions for gain and minimum control voltages of a bi-directional twodiode sampling gate.
Q2. Draw the sine-diode sampling gate and explain its operation.
Q3. What is sampling gate? Explain how it differs from logic gates?
Q4. Explain the basic principle of sampling gates.
Q5. With the help of a neat diagram, explain the working of two diode sampling gate.
Q6. Explain the operation of bi-directional sampling gate using diodes. Give the
equivalent circuit and derive the expression for gain. Derive the expressions for
minimum control voltages required.
Q7. Distinguish between logic gate and sampling gate.
Q8. Why is a sampling gate referred as a linear gate?
Q9. With a circuit diagram, explain the operation of unidirectional sampling gate for
multiple inputs.
Q10. What is sampling gate? How it differs from logic gates?
Q11. What is pedestal? How it effects the output of a sampling gate?
Q12. What are the draw backs of two diode sampling gate?
Q13. Draw the four diode sampling gate and explain its operation.
Q14. What is pedestal? How do we reduce it?
Q15. Differentiate between unidirectional and bidirectional gates.
Q16. Draw the circuit diagram of a sampling gate with more than one control voltage and
explain its working.
Q17. Draw and explain an emitter coupled bi-directional sampling gate.
Q18. For the four diode gate shown, with a divider resistance R used. Vs = 25V, Rf = 20
Ω, RL=RC=200K Ω, R=100 Ω. Find VC(min) , Vn(min) and A.
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Q19. Draw the transistor sampling gate and explain the operation.
Q20. Explain the operation of a linear gate using series switch and shunt switch. What are
the disadvantages?
Q21. Explain with circuit diagram, the operation of two input sampling gate which does
not have any loading effect on control signal.
Q22. Derive the expressions for gain and minimum control voltages of a bi-directional two
diode sampling gate.
Q23. What are the applications of sampling gates?
Q24. For the following circuit, Vs = 25V, Rf = 50 Ω, RL=RC=100KΩ, R2=2K Ω. Find VC(min)
, Vn(min) and A.
UNIT-8
Q1. Explain the operation of OR gate using diodes with its truth table.
Q2. Compare TTL and RTL logic.
Q3. Draw the AND gate using diodes and resistors and explain its operation.
Q4. Draw the transistor logic NAND gate and explain its operation.
Q5. Explain the working of INVERTER using transistor and resistors.
Q6. Compare DTL and RTL families.
Q7. Verify the truth table of DTL NAND gate with circuit diagram of two i/ps.
Q8. What is wired logic? Explain any wired logic circuit with example.
Q9. Define positive and negative logic systems.
Q10. Explain the operation of NOR gate using transistor with its truth table.
Q11. Draw a pulse train representing 11010111 in a synchronous positive logic digital
system.
Q12. Draw and explain the circuit diagram of a diode AND gate for positive logic.
Q13. Derive the o/p equation for a diode OR gate for positive logic.
Q14. Draw the circuit diagram and explain a DTL gate.
Q15. Verify the truth table of RTL NOR gate with circuit diagram of two i/ps.
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