Electric current can flow in two ways: alternating current (AC) and direct current (DC). The main difference between AC and DC lies in the direction in which the electrons flow. In DC, electrons flow steadily in a single direction, while in AC, electrons switch directions periodically.
What is an Alternating Current (AC)?
In alternating current, the electric charge flow changes direction periodically. AC is the most commonly used and preferred electric power for household equipment, offices, and buildings. It was first tested by Michael Faraday in 1832 using a Dynamo Electric Generator.
AC can be identified by a waveform called a sine wave, which represents electric cycles measured per second. This measurement is in Hertz (Hz). AC is used in powerhouses and buildings because it is relatively easy to generate and transport across long distances. AC can power electric motors used in refrigerators, washing machines, and other appliances.
What is Direct Current (DC)?
In direct current, the electric charge flows in a single direction in a steady voltage. The major use of DC is to supply power to electrical devices and charge batteries, such as mobile phone batteries, flashlights, flat-screen TVs, and electric vehicles. DC is represented by a plus and minus sign, a dotted line, or a straight line.
Everything that runs on a battery, uses an AC adapter, or relies on a USB cable for power, such as cellphones and electric vehicles, relies on DC. AC is converted to DC in many of these devices for proper functioning.
Comparison Table: AC vs. DC
| Feature | Alternating Current (AC) | Direct Current (DC) |
| Transmission Distance | Easy to transfer over long distances with minimal loss | Cannot be transferred over long distances effectively; loses power |
| Direction of Flow | Changes direction periodically | Flows in a single, steady direction |
| Frequency | Depends on the country (typically 50 Hz or 60 Hz) | Zero frequency |
| Electron Movement | Electrons change direction periodically (backward and forward) | Electrons move in one direction only (forward) |
| Generation | Generated by rotating magnets | Generated by steady magnets |
| Common Uses | Powerhouses, buildings, electric motors (refrigerators, washing machines) | Batteries, mobile phones, flashlights, electric vehicles |
FAQs
Common examples include batteries, mobile phones, flashlights, flat-screen TVs, and electric vehicles.
AC is converted to DC using a rectifier, which allows current to flow in only one direction.
The typical frequency of AC is either 50 Hz or 60 Hz, depending on the country.
Most household appliances run on AC, but devices like mobile phones, laptops, and some electric vehicles use DC, often converting AC to DC for their operation.
AC is used for long-distance power transmission because it can be easily transformed to high voltages, reducing energy loss during transmission.
The main difference is that AC current changes direction periodically, while DC current flows steadily in one direction.
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