Saturday 26 April 2014

PDC IMPORTANT QUESTIONS For External Exams


PDC IMPORTANT QUESTIONS


1. Obtain an expression for the input impedance of RC differentiating circuit. Compare it with that of RL differentiating circuit.
2. Explain the steps to analyze a clamping network with an example?
3. With neat sketches representing minority-carrier density distribution as a function of distance from junction, explain the diode reverse recovery time in detail?

4. List out differences between low pass and high pass filter.
5. Mention the differences between the types of multivibrators.
6. What is the use of clamper? Mention its real time examples.

7. With the help of neat diagram and wave forms explain the use of a monostable relaxation circuit as a frequency divider?
8. Explain negative peak clipper with and without reference voltage.
9. Write about diode switching times.

10. Explain the terms pertaining to transistor switching characteristics.
i) Rise time. ii) Delay time. iii) Turn-ON time.
iv) Storage time. v) Fall time. vi) Turn-OFF time.
11. What do you mean by collector catching diodes? Explain the need of these diodes in a bistable multivibrator.?

12. Draw the RC low pass circuit. With necessary waveforms and expressions explain its working for a step voltage input.

13. Prove that for any periodic input waveform the average level of the steady state output signal from the RC high pass circuit is always Zero.

14. With neat diagrams, explain the use of clamper circuit in television receivers as DC restorer? Write about diode switching times.
15. Draw and explain the circuit of Astable Multivibrator with necessary waveforms and also Derive the expression for its frequency of oscillations.
16. Explain the operations of a Trigger.
17. Explain the operation of common emitter bistable multivibrator.
18. Explain the transistor switching times.
19. Explain the operation of diode as a switch similarly explain transistor as a switch.
20. Explain the operation of transistor in saturation.


UNIT 5:

1) COMPARISION BETWEEN BOOTSTRAP AND MILLER SWEEP.
2) BOOTSTRAP SWEEP CIRCUIT.
3) UJT RELAXATION OSCILLATOR.
4) MILLER SWEEP CIRCUIT.
5) METHODS OF GENERATING TIME BASE GENERATORS.
6) EXPLAIN SIMOLE CURRENT TIME BASE GENERATORS.

UNIT 6:

7) WHAT IS SYNCHRONISATION AND FREQUENCY DIVISION.
8) ASTABLE SYNCHRONISATION.
9) MONOSTABLE SYNCHRONISATION.
10) SYMMETRICAL SYNCHRONISATION FOR SWEEP CIRCUIT.

UNIT 7:

11) WHAT IS SAMPLING GATE? DIFFERENCES BETWEEN SAMPLING ANG LOGIC GATES.
12) UNIDIRECTIONAL SAMPLING GATE USING DIODES.
13) BIDIRECTIONAL SAMPLING GATES USING ONE AND TWO TRANSISTORS.
14) HOW CAN WE ELIMINATE PEDESTAL.
15) 2,4,6 DIODES.
16) APPLICATIONS OF SAMPLING GATES.

UNIT 8:

17) TTL.
18) CMOS, NAND, NOR.
19) DTL.
20) COMPARE ECL, IIR WITH SPECIFICATIION.

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