vaihtovirrassa

Vaihtovirrassa, often translated as alternating current (AC), is an electric current that periodically reverses direction. This is in contrast to direct current (DC), which flows in only one direction. The fundamental characteristic of AC is its sinusoidal waveform, meaning the voltage and current vary smoothly over time, peaking at regular intervals and then reversing to peak in the opposite direction.

The generation of AC is typically accomplished by rotating a coil of wire within a magnetic field or by rotating a magnetic field near a stationary coil. This process, governed by Faraday's law of induction, induces a continuously changing voltage and thus a flow of alternating current. A key advantage of AC is its ability to be easily transformed to higher or lower voltages using transformers. This property is crucial for efficient long-distance power transmission. High voltages are used to minimize energy loss during transmission, and then transformers step down the voltage to safer levels for use in homes and industries.

Most household electrical outlets provide AC power. The frequency of AC varies by region; in Europe and many other parts of the world, it is 50 Hertz (Hz), meaning the current reverses direction 50 times per second. In North America, the standard frequency is 60 Hz. This alternating nature allows for the operation of a wide range of electrical devices, including motors, lighting, and many electronic appliances.