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    Unit-V Blocking Oscillators and Time Base Generators Two Marks Question & Answer

    Uploaded by

    Jayed Ahmed Laskar
    This document contains questions and answers related to the topics of blocking oscillators and time base generators. It defines key terms such as blocking oscillator, time base generator, UJT, pulse transformer applications, and sweep parameters. It also provides explanations of pulse transformers, monostable blocking oscillators using emitter timing, core saturation method of pulse generation, astable blocking oscillators, and UJT sawtooth generators.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Unit-V Blocking Oscillators and Time Base Generators Two Marks Question & Answer

    Uploaded by

    Jayed Ahmed Laskar
    121 views3 pages
    This document contains questions and answers related to the topics of blocking oscillators and time base generators. It defines key terms such as blocking oscillator, time base generator, UJT, pulse transformer applications, and sweep parameters. It also provides explanations of pulse transformers, monostable blocking oscillators using emitter timing, core saturation method of pulse generation, astable blocking oscillators, and UJT sawtooth generators.

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    QB106425_3

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    This document contains questions and answers related to the topics of blocking oscillators and time base generators. It defines key terms such as blocking oscillator, time base generator, UJT, pulse transformer applications, and sweep parameters. It also provides explanations of pulse transformers, monostable blocking oscillators using emitter timing, core saturation method of pulse generation, astable blocking oscillators, and UJT sawtooth generators.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    121 views3 pages

    Unit-V Blocking Oscillators and Time Base Generators Two Marks Question & Answer

    Uploaded by

    Jayed Ahmed Laskar
    This document contains questions and answers related to the topics of blocking oscillators and time base generators. It defines key terms such as blocking oscillator, time base generator, UJT, pulse transformer applications, and sweep parameters. It also provides explanations of pulse transformers, monostable blocking oscillators using emitter timing, core saturation method of pulse generation, astable blocking oscillators, and UJT sawtooth generators.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 3

    SRI VIDYA COLLEGE OF ENGG & TECH

    DEPARTMENT OF ECE
    EC 6401 – Electronic Circuits II

    UNIT-V BLOCKING OSCILLATORS


    AND TIME BASE GENERATORS
    Two Marks Question & Answer

    1. What is Blocking Oscillator?


    A special type of wave generator which is used to produce a single narrow pulse or
    train of pulses using regenerative feedback characteristics are called Blocking oscillator.
    2. What are Time Base generators?
    The circuits which provide an output waveform, a part of which is characterized
    by a linear variation of voltage or current with respect to time are called Time Base
    generators.
    3. What is UJT?
    1. UJT is a three terminal semiconductor switching device.
    2. As it has only one PN junction and three leads, it is commonly called
    as Uni-junction transistor.
    4. What are the two important elements of Blocking
    Oscillator? Transistor and pulse transformer
    5. What are the applications of blocking Oscillator?
    It is used in frequency dividers, counter circuits and for switching the other circuits.
    6. Give the expression for co-efficient of
    coupling K=M/√LpLs
    M-> Mututal Inductance, Lp -> Primary Inductance, Ls -> Secondary Inductance
    7. Give the formula for transformation
    ratio n= Ns/Np = transformation
    ratio
    Ns= Secondary Turns; Np= Primary turns
    8. Define rise time.
    It is defined by the time required by the pulse to rise from 10% of its amplitude to
    90% of its amplitude.
    9. Define overshoot.
    It is the amount by which the output exceeds its amplitude during first attempt.
    10. What is leading edge response?
    At start there is an overshoot and then pulse settles down. The response till it
    settles down after the overshoot is called leading edge response.
    11. What is trailing edge response?
    The response generally extends below the zero amplitude after the end of pulse
    width is called back swing. The portion of response from back swing till it settles down is
    called trailing edge response.
    12. Define flat top response.
    The portion of the response between the trailing edge and the leading edge is
    called flat top response.
    13. Define droop or a tilt.
    The displacement of the pulse amplitude during its flat response is called droop or
    a tilt.
    14. What are the applications of pulse
    transformer? Pulse transformer can be
    used to
    1. Change the amplitude and impedance level of a pulse.
    2. Invert the polarity of the pulse.
    3. Produce a pulse in a circuit having negligible d.c. resistance.
    4. Differentiate a pulse.
    5. Act as a coupling element in a certain pulse generating circuits.
    15. When does the core saturate?
    When L->o as B-> Bm, the core saturates.
    16. What is the other name of astable Blocking
    Oscillator? Free running blocking Oscillator.
    17. What are the two types of astable Blocking Oscillator?
    1. Diode controlled Astable Blocking Oscillator.
    2. Re controlled Astable Blocking Oscillator.
    18. Define Sweep time in saw tooth generator.
    The period during which voltage increases linearly is called sweep time.
    19. What is the other name of saw tooth generator?
    Ramp generator.
    20. Define Displacement error in the saw tooth generator?
    It is defined as the maximum differences between the actual sweep voltage and
    linear sweep which passes through the beginning and end points of the actual sweep.
    21. What is constant current charging?
    A capacitor is charged with a constant current source.
    22. What is the miller circuit?
    Integrator is used to convert a step waveform into ramp waveform.
    23. Mention the various methods of controlling the pulse.
    1. Use of common base configuration.
    2. Use of common collector configuration.
    3. Use of core saturation method.
    4. Use of shorted delay line.
    24. What is mark space ratio?
    The ratio of time for which Q is On to time for which Q is OFF is called mark-
    space ratio. If this is unity, then the output is almost symmetrical square wave.
    25. Define Duty cycle.
    The duty cycle is defined as the ratio of the ON time tp to the time period T.
    Mathematically it is given by, D= tp/T
    26. How high duty cycle is obtained?
    1. Using temperature compensated zener diode.
    2. Using Ge diode in series with tertiary winding across the supply voltage.
    27. What do you mean by voltage time base generators?
    Circuits used to generate a linear variation of voltage with time are called Voltage
    time-base generators.
    28. What do you mean by linear time base generators/
    Circuits provide an output waveform which exhibits a linear variation of voltage
    with time are called linear time base generators.
    29. Define restoration time or flyback time.
    The time required for the return for the sweep voltage to the initial value is called
    restoration time (or) return time (or) flyback time.
    30. Define sweep time.
    The period during which voltage increases linearly is called sweep time.
    31. List important sweep parameters.
    Sweep speed error, Displacement error and transmission error.
    32. Name the different errors in generation of sweep waveforms.
    Sweep speed error, Displacement error and transmission error.
    33. Define Sweep speed error.
    It is the ratio of difference in slope at beginning and end of sweep to the initial
    value of slope.
    34. Define Displacement error.
    It is defined as the maximum difference between the actual sweep voltage and
    linear sweep which passes through the beginning and end points of the actual sweep.
    35. Define transmission error.
    When a ramp voltage is transmitted through a high-pass RC network, its output
    falls away from the input. The transmission error is defined as the difference between the
    input and output divided by the input.
    16 marks Question

    1. Explain about pulse transformer?


    2. Explain Monostable blocking oscillator using emitter timing?
    3. Write about the core saturation method.
    4. Write about astable blocking oscillator.
    5. Write about UJT saw tooth generator

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