Measurements of AC magnitude

Chapter 1.3 Measurements of AC magnitude

Lessons In Electric Circuits Volume II – AC Book
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Lessons In Electric Circuits Volume II – AC Book

  • 1.3.MEASUREMENTS OF AC MAGNITUDE11Square waveTriangle waveSawtooth waveone wave cycleone wave cycleFigure 1.13: Some common waveshapes (waveforms).These waveforms are by no means the only kinds of waveforms in existence. They’re simply afew that are common enough to have been given distinct names. Even in circuits that are supposedto manifest “pure” sine, square, triangle, or sawtooth voltage/current waveforms, the real-life resultis often a distorted version of the intended waveshape. Some waveforms are so complex that theydefy classification as a particular “type” (including waveforms associated with many kinds of musicalinstruments). Generally speaking, any waveshape bearing close resemblance to a perfect sine waveis termed sinusoidal, anything different being labeled as non-sinusoidal. Being that the waveform ofan AC voltage or current is crucial to its impact in a circuit, we need to be aware of the fact thatAC waves come in a variety of shapes.• REVIEW:• AC produced by an electromechanical alternator follows the graphical shape of a sine wave.• One cycle of a wave is one complete evolution of its shape until the point that it is ready torepeat itself.• The period of a wave is the amount of time it takes to complete one cycle.• Frequency is the number of complete cycles that a wave completes in a given amount of time.Usually measured in Hertz (Hz), 1 Hz being equal to one complete wave cycle per second.• Frequency = 1/(period in seconds)1.3Measurements of AC magnitudeSo far we know that AC voltage alternates in polarity and AC current alternates in direction. Wealso know that AC can alternate in a variety of different ways, and by tracing the alternation over