Vaihtojännite

Vaihtojännite, 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 voltage of an AC source also periodically reverses polarity. This characteristic variation in voltage and current is typically sinusoidal, meaning it follows a sine wave pattern. The frequency of the alternating current, measured in Hertz (Hz), indicates how many times the current reverses direction per second. For example, in Europe, the standard frequency is 50 Hz, while in North America it is 60 Hz.

The primary advantage of AC over DC is its ability to be easily transformed to higher or lower voltages using transformers. This makes it highly efficient for long-distance power transmission, as high voltages reduce power loss. Conversely, voltages can be stepped down to safer levels for use in homes and businesses. Many common electrical devices, such as lights, motors, and most household appliances, are designed to operate on AC power. The generation of AC electricity typically occurs in power plants using rotating generators, which convert mechanical energy into electrical energy through electromagnetic induction.