váltakozóáramot

Váltakozóáramú, often abbreviated as AC, is an electric current that periodically reverses direction and changes its magnitude continuously over time. This is in contrast to direct current (DC), where the electric charge flows consistently in one direction. The most common waveform for AC is a sinusoidal wave, meaning the voltage and current follow a sine function.

The primary advantage of AC over DC is its ease of voltage transformation. Alternating current can be efficiently stepped up to high voltages using transformers for long-distance transmission, which significantly reduces energy loss due to resistance in the wires. Conversely, it can be stepped down to lower, safer voltages for use in homes and businesses. This ability to efficiently change voltage levels is crucial for modern electrical grids.

AC power is generated by rotating electrical machines called alternators. These devices use the principle of electromagnetic induction, where a changing magnetic field induces an electromotive force (voltage) in a conductor. In power plants, mechanical energy, often from steam turbines or water turbines, is used to spin alternators, producing the electricity that powers our world.

The frequency of AC power varies by region. In North America, the standard frequency is 60 Hertz (Hz), meaning the current reverses direction 60 times per second. In most of Europe and many other parts of the world, the standard is 50 Hz. This frequency determines how quickly the AC waveform cycles. Household appliances and electronic devices are designed to operate at these specific frequencies.