vaihtovirrän

Vaihtovirta, or alternating current (AC), is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction. The waveform of AC is typically sinusoidal, meaning the voltage and current vary smoothly and predictably over time. This sinusoidal nature is crucial for efficient generation and transmission of electrical power.

The primary advantage of AC over DC is its ability to be easily transformed to different voltage levels using transformers. This allows electricity to be generated at a relatively low voltage, stepped up to a very high voltage for efficient long-distance transmission with minimal energy loss, and then stepped down again to safer, usable voltages for homes and businesses. This voltage transformation is not feasible with DC.

AC power is the standard form of electrical power used in electrical grids worldwide. It is generated by rotating machinery, such as alternators in power plants, where the rotation of magnets within coils of wire induces a continuously changing current. The frequency of AC, measured in Hertz (Hz), indicates how many times the current reverses direction per second. In most parts of the world, the standard frequency is 50 Hz or 60 Hz.

While AC is dominant for power distribution, DC is still used in many applications, such as in batteries, electronics, and specific industrial processes. However, for large-scale power transmission and distribution, AC remains the most practical and economical choice.