Why Sine Waveform Chosen for Alternating Voltage and Current

Commercial alternators produce sinusoidal alternating voltage. A sinusoidal alternating voltage is produced by rotating a coil with a constant angular velocity in a uniform magnetic field. Sinusoidal voltage always produce sinusoidal current unless the circuit is non linear.

Why Sine Wave is chosen rather than a simple curve such as a square or triangular wave. Some of the reasons are given below:

• In alternating current (a.c) machines such as induction machines, synchronous machines, transformers.., sinusoidal voltages and currents respectively produce the least iron and copper losses for a given output. The efficiency of the machine therefore is better
• Sinusoidal voltages and currents produce less interference (noise) on telephone lines
• The sine waveform produces the least disturbance in the electrical circuit and is smoothest and efficient waveform

Due to above advantages, electrical supply is generate sinusoidal alternating voltage and currents.