Vekselspænding

Vekselspænding, often abbreviated as AC (Alternating Current), is an electric current which periodically reverses direction, unlike direct current (DC) which flows only in one direction. This reversal of direction is accompanied by a reversal of voltage. The waveform of vekselspænding is typically sinusoidal, meaning it follows a sine wave pattern over time. The key characteristics of vekselspænding are its frequency and its amplitude. Frequency refers to the number of complete cycles of the current or voltage that occur in one second, measured in Hertz (Hz). Amplitude, also known as the peak voltage or peak current, represents the maximum value the voltage or current reaches during a cycle.

Vekselspænding is the standard form of electrical power distribution used in most countries because it can be efficiently transformed to higher voltages for transmission over long distances and then stepped down to lower, safer voltages for use in homes and businesses. This transformation is achieved using transformers, which rely on the principle of electromagnetic induction and only work with alternating currents. Common frequencies for power grids are 50 Hz or 60 Hz. Applications of vekselspænding are widespread, powering everything from household appliances and lighting to industrial machinery. The generation of vekselspænding is typically done by rotating machines called alternators, where mechanical energy is converted into electrical energy.