Vahelduvvooluks

Vahelduvvooluks, often abbreviated as AC (Alternating Current), is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. The waveform of AC in most power systems is a sinusoidal wave, though other waveforms like triangular or square waves are also used. The primary advantage of AC is that its voltage can be easily increased or decreased using a transformer, allowing for efficient long-distance transmission at high voltages and then reduction to safer, usable voltages for homes and businesses.

The generation of AC typically occurs in alternators, which are rotating machines that convert mechanical energy into electrical energy. The frequency of AC, measured in Hertz (Hz), is the number of cycles the current completes in one second. In most of the world, the standard frequency is 50 Hz, while in North America it is 60 Hz. This frequency determines how many times the current reverses direction per second.

The concept of AC was largely developed by Nikola Tesla and George Westinghouse, who championed its adoption over DC, which was primarily promoted by Thomas Edison. The "War of Currents" in the late 19th century ultimately saw AC emerge as the dominant system for power distribution due to its advantages in transmission efficiency and voltage manipulation. Modern electrical grids rely heavily on AC for delivering power to consumers.