Electrical Engineering ⇒ Topic : Sine Waveform

Sunita
 
Although it is possible to produce alternating voltages and currents with an endless variety of waveforms (e.g., square waves, triangular waves, rectangular waves etc), yet the engineers choose to adopt **sine waveform. The following are the technical and economical advantages of producing sinusoidal alternating voltages and currents (i) The sine waveform produces the least disturbance in the electrical circuit and is the smoothest and efficient waveform. For example, when current in a capacitor, in an inductor or in a transformer is sinusoidal, the voltage across the element is also sinusoidal. This is not true of any other waveform. (ii) The use of sinusoidal voltages applied to appropriately designed coils results in a revolving magnetic field which has the capacity to do work. In fact, it is this principle which underlines the operation of induction motors which form about 90% of all electric motors found in commercial and industrial applications. Although other waveforms can be used, none leads to an operation which is as efficient and economical as that achieved through the use of sinusoidal voltages and currents. (iii) The mathematical computations, connected with alternating current work, are much simpler with this waveform. (iv) By means of Fourier series analysis, it is possible to represent any periodic function of whatever waveform in terms of sinusoids. This is a notable advantage in the mathematical sense because nonsinusoidal waves can be analysed in terms of sinusoids. Due to above advantages, electric supply companies all over the world generate sinusoidal alternating voltages and currents. It may be noted that alternating voltage and current mean sinusoidal alternating voltage and current unless stated otherwise.  
 
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