Alternatiivvoolud

Alternatiivvoolud, commonly known as AC (alternating current), refers to the flow of electric charge that periodically reverses direction. This is in contrast to direct current (DC), where the charge flows in only one direction. In AC circuits, the voltage and current vary sinusoidally over time, oscillating between positive and negative values. The rate at which this oscillation occurs is called the frequency, measured in Hertz (Hz). For example, in most countries, the standard mains electricity frequency is 50 Hz or 60 Hz, meaning the current changes direction 50 or 60 times per second.

The primary advantage of AC over DC is its ease of voltage transformation. Using transformers, AC voltage can be efficiently stepped up or down. This is crucial for power transmission, as high voltages are used to minimize energy loss over long distances, and then stepped down to safer, usable levels for homes and businesses. AC generators, such as those found in power plants, naturally produce alternating current. Motors designed for AC are generally simpler and more robust than their DC counterparts.

While AC is dominant in power grids and many electronic devices, DC is still essential for many applications, particularly in battery-powered devices and sensitive electronics that require a stable, unidirectional current. Many modern electronic devices, like computers and smartphones, internally convert AC from the mains supply to DC for their internal circuitry using power adapters and internal regulators. The widespread adoption of AC for power distribution is a testament to its practical advantages in generating, transmitting, and utilizing electrical energy.