Alternating Voltage (AC), also known as Alternating Current, is an electric current that periodically reverses direction. Unlike Direct Current (DC), which flows consistently in one direction, AC changes its polarity and magnitude over time. This variation in direction and magnitude makes AC well-suited for transmitting electrical power over long distances and for many applications in our daily lives.
AC voltage is typically represented by a sinusoidal waveform, also known as a sine wave. In a sine wave, the voltage or current smoothly alternates between positive and negative values, reaching its peak positive and negative values at regular intervals. The frequency of the AC waveform is the number of complete cycles (from one peak to the next) that occur in one second and is measured in Hertz (Hz).
Common household AC voltage standards vary around the world. For example, in the United States, the standard AC voltage is 120 volts at 60 Hz, while in Europe, it's 230 volts at 50 Hz. AC power is delivered to homes, businesses, and industries for various applications, including lighting, heating, air conditioning, motors, and electronic devices.
The ability to easily transform AC voltage using transformers and to transmit it over long distances with minimal loss are significant advantages of AC over DC. This is why AC has become the dominant choice for electricity distribution in most power grids and systems worldwide.