In alternating current (AC, also ac), the movement of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge is only in one direction. The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.[1] [2] AC is the form in which electric power is delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.

# How does alternating current work?

1. ## Generating AC Power

• Alternating Current (AC) is a form of electrical current where the polarity and direction reverses in regular cycles. The basic AC generator uses a coiled conductive wire called an armature, which is rotated in the field created between two magnets. The constant motion of the armature creates the electrical current, and its changing position relative to the magnetic field causes the "alternation." This is different from Direct Current (DC), where the polarity and direction are constant. A common DC power source is a battery.

## Transforming the Voltage

• At the power generating station, a device called a transformer is used to increase the voltage of the electricity. This is done because high voltage is easier to transmit over long distances, allowing the power station to be located further away from the eventual consumers of the electricity. While more efficient for distribution over long distances, high voltage power also requires substantial insulation and extra safety measures.

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• When the electricity reaches the vicinity of its customers, it is fed through another transformer at a substation, reducing the voltage from its high, long-distance transmission level to a level suitable for local distribution.

• The final stage is when the electricity reaches your local transformer. If you live in an area where power lines are strung on poles, you can identify your local transformer. They are the large metal cylinders at the top of the poles that the power lines are fed through. Each local transformer feeds one to three homes or other units, like businesses. This is the final stage of voltage reduction, with the electricity being reduced to the standard level for everyday consumption.

Power By How it Work

20th Jan 2015

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