In class 12 physics, AC circuits refer to the study of circuits in which the current and voltage periodically vary with time in the form of an alternating current (AC). The topic covers concepts such as RMS value of AC current and voltage, reactance and impedance, power factor, resonance in series and parallel circuits, and the behaviour of AC circuits containing capacitors and inductors.
Understanding AC circuits is essential in various fields such as electrical engineering, electronics, and telecommunications. It is used in the design and functioning of various electrical devices such as motors, generators, transformers, and power transmission systems. Additionally, knowledge of AC circuits is crucial in the study of electromagnetic waves, which form the basis of wireless communication technologies.