RMS and Average value, Peak and Form Factor of Half Wave Alternating Current

Half wave rectified alternating current is one which flows for half the time during one cycle. It is illustrated in figure 1 where suppressed half cycle is shown dotted. As mentioned earlier, for determining rms and average value of such an alternating current summation would be carried over the period for which current actually flows i.e. 0 to π but would be average for the whole cycle i.e. from 0 to 2π. RMS value of current, = = = = = Average value of current, = Peak Factor = Form…

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Graphical or Phasor Representation of Alternating Quantities

It has already been pointed out that it is assumed that alternating voltages and currents follow sine law and generators are designed to give emfs having sine waveform. The above said assumption makes the calculations simple. The method of representing alternating quantities by waveform or by the equations giving instantaneous values is quite cumbersome. For solution of ac problems, it is advantageous to represent a sinusoidal quantity (voltage or current) by a line of definite length rotating in counter-clockwise (It is a standard convention that the phasor is rotated in…

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Average and RMS Value of Alternating Current and Voltage

Average and RMS Value of Alternating Current and Voltage: In a dc system, the voltage and current are constant and, therefore, there is no problem in specifying their magnitude. But in case of ac system, an alternating voltage or current varies from instant to instant and so poses a problem how to specify the magnitude of an alternating voltage or current. An alternating voltage or current may possibly be expressed in terms of peak (maximum) value, average (mean) value or effective (rms) value. In specifying an alternating voltage or current,…

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Alternating Waveform | Instantaneous value | Time period | Amplitude

An alternating quantity (voltage or current) is one which changes continuously in magnitude and alternates in direction at regular intervals of time. It rises from zero to maximum positive value, falls to zero, increases to a maximum in the reverse direction and falls back to zero again, as illustrated in Fig. 1. The emf (or voltage) and current repeat the procedure. The important ac terms are defined below: Waveform The shape of the curve of the voltage or current when plotted against time as abscissa (base) is called the waveform.…

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Fundamental and Generation of Alternating Current

Fundamental and Generation of Alternating Current: A current (or voltage) is called alternating if it reverses periodically in direction, and its magnitude undergoes a definite cycle of changes in definite intervals of time. Each cycle of alternating current (or voltage) consists of two half cycles, during one of which the current (or Voltage) acts in one direction; while during the other in opposite direction. In more restricted sense, alternating current is a periodically varying current, the average value of which, over a period, is zero. The direct current always flows…

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