Electrical Waveforms Quiz
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Questions and Answers

What determines the direction of current movement in an AC circuit?

  • Amplitude
  • Frequency
  • Phase angle
  • Terminal voltage polarities (correct)

    • What is the amplitude in the context of AC alternations?

  • The frequency of the alternating current
  • The phase difference between positive and negative alternations
  • The rate of change of induced EMF
  • The distance from zero to the maximum value of each alternation (correct)

    • How does AC differ from DC in terms of current flow?

  • Generates a constant force on electrons
  • Has a constant amplitude
  • Has a fixed phase angle
  • Flows first in one direction and then in the opposite direction (correct)

    • What is the most common waveform for AC power?

    <p>Sine (or sinusoidal) waveform</p> Signup and view all the answers

    What produces a greater force to drive electrons in a conductor?

    <p>Cutting lines of flux quickly</p> Signup and view all the answers

    How does the number of poles in a generator affect the cycles completed in a revolution?

    <p>Increases the number of cycles completed</p> Signup and view all the answers

    When does the peak value of a sine wave occur?

    <p>Twice each cycle</p> Signup and view all the answers

    What does instantaneous value of voltage or current represent?

    <p>Value at any time on the sine wave</p> Signup and view all the answers

    What is the magnitude called that represents the voltage or current between the peak positive and peak negative values?

    <p>Peak-to-peak value</p> Signup and view all the answers

    What is the key factor that determines the induced voltage in a generator?

    <p>The strength of the magnetic field</p> Signup and view all the answers

    What is the primary reason for the sinusoidal waveform produced by a generator?

    <p>The changing angle between the armature conductors and the magnetic field</p> Signup and view all the answers

    What is the significance of the armature conductors being parallel to the magnetic field at the 0° position?

    <p>It results in no induced voltage</p> Signup and view all the answers

    How does the induced voltage change as the armature rotates from 90° to 180°?

    <p>It decreases from a maximum positive value to zero</p> Signup and view all the answers

    What is the significance of the armature conductors cutting through the magnetic field in the opposite direction from 180° to 270°?

    <p>It results in a negative induced voltage that builds up to a maximum at 270°</p> Signup and view all the answers

    Which of the following is the primary factor that determines the shape of an AC waveform?

    <p>The method used to generate the AC power</p> Signup and view all the answers

    What is the relationship between the angle of rotation of an alternator and the amplitude of the resulting sinusoidal AC waveform?

    <p>The amplitude is directly proportional to the angle of rotation</p> Signup and view all the answers

    What is the primary advantage of using a sinusoidal AC waveform compared to a non-sinusoidal waveform in power distribution systems?

    <p>Sinusoidal waveforms are easier to transform using a transformer</p> Signup and view all the answers

    Which of the following electronic circuits is MOST likely to produce a non-sinusoidal AC waveform?

    <p>A full-wave rectifier</p> Signup and view all the answers

    What is the primary advantage of using a three-phase AC generator (alternator) compared to a single-phase generator?

    <p>Three-phase generators can produce higher power output</p> Signup and view all the answers

    In a three-phase AC generator, what is the phase difference between the voltage waveforms of the three phases?

    <p>120 degrees</p> Signup and view all the answers

    If Phase A voltage in a three-phase system reaches its positive peak at 0 degrees, at what angle does Phase B voltage reach its positive peak?

    <p>120 degrees</p> Signup and view all the answers

    Which of the following waveforms is not mentioned as an example of an AC signal type in the given text?

    <p>Gaussian wave</p> Signup and view all the answers

    What is the distinguishing feature of alternating waveforms mentioned in the text?

    <p>They have equal areas enclosed above and below the time axis</p> Signup and view all the answers

    If Phase A voltage in a three-phase system is represented by $V_A = V_m \sin(\omega t)$, what would be the expression for Phase B voltage?

    <p>$V_B = V_m \sin(\omega t + \frac{2\pi}{3})$</p> Signup and view all the answers

    In a balanced three-phase AC system, the phase angle between any two adjacent phases is:

    <p>120 degrees</p> Signup and view all the answers

    The frequency of the output voltage in a three-phase generator is primarily determined by:

    <p>Both the number of poles and the speed of rotation</p> Signup and view all the answers

    In a series LCR circuit, if the inductive reactance is equal to the capacitive reactance, the phase angle between the applied voltage and the current will be:

    <p>0 degrees (in phase)</p> Signup and view all the answers

    In a series LCR circuit, the phase angle of the circuit current $I_T$ with respect to the applied voltage is determined by:

    <p>The ratio of the difference between $V_C$ and $V_L$ to $V_R$</p> Signup and view all the answers

    In a three-phase generator, if the number of poles is increased while the rotational speed remains constant, the output frequency will:

    <p>Increase</p> Signup and view all the answers

    Which waveform can be generated using a simple DC circuit that measures the voltage at a capacitor that is gradually charged and rapidly discharged?

    <p>Triangular wave</p> Signup and view all the answers

    What is the key difference between a sawtooth wave and a triangular wave?

    <p>The timing associated with the rise and fall of the wave shape</p> Signup and view all the answers

    What is the identifying feature of a sawtooth wave?

    <p>Unequal rise and fall times</p> Signup and view all the answers

    What is the simplest square wave generator mentioned in the text?

    <p>Switch: on and off</p> Signup and view all the answers

    At what speed can current CPU clocks operate, according to the text?

    <p>&gt;4.0 GHz</p> Signup and view all the answers

    What type of generator is used by current computer processors for clock pulses?

    <p>Square wave generator</p> Signup and view all the answers

    What feature distinguishes a square wave generator from other waveforms?

    <p>Different rise and fall times</p> Signup and view all the answers

    What unique characteristic defines a triangular waveform in comparison to a sawtooth waveform?

    <p>Equal rise and fall time periods</p> Signup and view all the answers

    What determines the speed capability of a simple square wave generator?

    <p>&gt;4.0 GHz frequency operations</p> Signup and view all the answers

    How does the timing of a triangular wave differ from that of a sawtooth wave?

    <p>Equal rise and fall times in a triangular wave compared to unequal in a sawtooth wave.</p> Signup and view all the answers

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