Alternating Current

What “Alternating Current” begins with

7.1 INTRODUCTION We have so far considered direct current (dc) sources and circuits with dc sources. But voltages and currents that vary with time are very common. The electric mains supply in our homes and offices is a voltage that varies like a sine function with time. Such a voltage is called alternating voltage (ac voltage) and the current driven by it in a circuit is called the alternating current (ac current)*.