växelströmen

Växelström, often abbreviated as AC (alternating current), is an electric current that periodically reverses direction. This is in contrast to direct current (DC), where the flow of charge is always in one direction. The defining characteristic of AC is its sinusoidal waveform, although other waveforms are also possible. The voltage and current in an AC system oscillate, meaning they rise to a maximum value in one direction, fall to zero, and then rise to a maximum value in the opposite direction before repeating the cycle.

The frequency of AC is the number of complete cycles per second, measured in Hertz (Hz). In most of the world, the standard frequency for AC power distribution is 50 Hz or 60 Hz. The voltage in an AC system can be easily stepped up or down using transformers, a key advantage that makes it suitable for long-distance power transmission. High voltages are used to transmit electricity efficiently over long distances, reducing energy loss, and then stepped down to safer, usable levels for homes and businesses.

Nikola Tesla is widely credited with developing the AC electrical system, which ultimately proved superior to Thomas Edison's direct current system for widespread power distribution. The widespread adoption of AC has enabled the development of many electrical appliances and technologies that are integral to modern life.