Vahelduvvoolust

Vahelduvvoolust, 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 term "vahelduvvoolust" directly translates from Estonian to "alternating current". In AC, the magnitude of the voltage and current varies sinusoidally over time. This is the form of electrical energy generated by power plants and distributed through the electrical grid to homes and businesses.

The primary advantage of AC over DC is its ability to be easily transformed to higher or lower voltages. This is achieved using transformers, which are crucial for efficient long-distance transmission of electricity. High voltages are used to reduce power loss during transmission, and then these voltages are stepped down to safer levels for use in homes and appliances. The frequency of AC is typically measured in Hertz (Hz), representing the number of cycles per second. In most of the world, this frequency is 50 Hz or 60 Hz. Early electrical systems, like the one championed by Thomas Edison, used direct current, but Nikola Tesla's advocacy for alternating current, supported by George Westinghouse, ultimately led to AC becoming the standard for power distribution due to its inherent advantages in transmission and voltage transformation.