Telexplainer is a technical and business blog about telecommunications and IT networking developments.
Also see current, voltage, and direct current. In electricity, alternating current (AC) occurs when charge carriers in a conductor or semiconductor periodically reverse their direction of movement. Household utility current in most countries is AC with a frequency of 60 hertz (60 complete cycles per second), although in some countries it is 50 Hz. The radio-frequency (RF) current in antennas and transmission lines is another example of AC. An AC waveform can be sinusoidal, square, or sawtooth-shaped. Some AC waveforms are irregular or complicated. An example of sine-wave AC is common household utility current (in the ideal case).
(Note that the high-frequency ripples in the current are at low magnitude, and the additional heat is in the order of 5% to 10% above that produced by a pure sine wave). The synchronous speed of a four-pole motor served by 60-Hz power is 1800 rpm. This same motor, when considering overtones or ripples in the current's fundamental frequency caused by a voltage carrier frequency of 4 kHz, will have current flowing through it based on that high frequency.