It is common to use sinusoids and phasors to analyze AC circuits. So it is important to learn them.

The reasons behind the use of sinusoids in AC circuit analysis are,

1. Almost all natural phenomena have sinusoidal characteristics.
2. Signals in the sinusoidal form are simple to generate and transmit.
3. Using Fourier analysis, any practical periodic signal can be represented as a sum of sinusoids.
4. Mathematically, a sinusoid is easy to handle

Confused? don’t worry, I’ll explain each one to you.

First, nature itself is characteristically sinusoidal. There is a sinusoidal variation in the motion of most natural phenomena. Some examples include the motion of a pendulum, the vibration of a string, the ripples on the ocean texture, and the natural response to underdamped second-order systems.