Electrical Engineering ⇒ Topic : Average Value
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David
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Average Value The average value of a waveform is the average of all its values over a period of time. In performing such a computation, we regard the area above the time axis as positive area and area below the time axis as negative area. The algebraic signs of the areas must be taken into account when computing the total (net) area. The time interval over which the net area is computed is the period T of the waveform. (i) In case of *symmetrical waves (e.g. sinusoidal voltage or current), the average value over one cycle is zero. It is because positive half is exactly equal to the negative half so that net area is zero. However, the average value of positive or negative half is not zero. Hence in case of symmetrical waves, average value means the average value of half-cycle or one alternation (ii) In case of unsymmetrical waves (e.g. half-wave rectified voltage etc.), the average value is taken over the full cycle. The average value of a waveform is also called its d.c. value. In fact, when a waveform is measured with a d.c. instrument (d.c. ammeter or d.c. voltmeter), it is the average value of the waveform that is indicated by the instrument. | |
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David
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Average Value The average value of a waveform is the average of all its values over a period of time. In performing such a computation, we regard the area above the time axis as positive area and area below the time axis as negative area. The algebraic signs of the areas must be taken into account when computing the total (net) area. The time interval over which the net area is computed is the period T of the waveform. (i) In case of *symmetrical waves (e.g. sinusoidal voltage or current), the average value over one cycle is zero. It is because positive half is exactly equal to the negative half so that net area is zero. However, the average value of positive or negative half is not zero. Hence in case of symmetrical waves, average value means the average value of half-cycle or one alternation (ii) In case of unsymmetrical waves (e.g. half-wave rectified voltage etc.), the average value is taken over the full cycle. The average value of a waveform is also called its d.c. value. In fact, when a waveform is measured with a d.c. instrument (d.c. ammeter or d.c. voltmeter), it is the average value of the waveform that is indicated by the instrument. | |
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