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What is AC (Alternating Current)?

Alternating Current (AC) is a form of electricity where the flow of electrons reversesdirection periodically, unlike Direct Current (DC), where the flow isunidirectional. AC is the standard for power transmission and distributionworldwide due to its ability to travel long distances efficiently and betransformed into different voltages using transformers. Alternating current has:

• Waveform: AC typically follows a sinusoidal wave, allowing for smooth andconsistent power delivery.
• Frequency: Commonly 50 Hz (cycles per second) in most of the world, 60 Hz inregions like North America.
• Voltage: Constantly rises and falls, changing polarity at each half-cycle.

Diagram: Sinusoidal Wave of AC vs. DC

Alternating Current (AC) is a form of electricity where the flow of electrons reversesdirection periodically, unlike Direct Current (DC), where the flow isunidirectional. AC is the standard for power transmission and distributionworldwide due to its ability to travel long distances efficiently and betransformed into different voltages using transformers. Alternating current has:

How Does AC Work?

AC works on the principle of electromagnetic induction,discovered by Michael Faraday. An alternator (AC generator) spins a coilof wire inside a magnetic field, inducing an oscillating electric current.

AC is generated by devices known as alternators or AC generators,which operate using electromagnetic induction.

AC Generation:

• A coil spins within a magnetic field (or vice versa).
• This induces an oscillating voltage as per Faraday’s Law.
• The output is a sinusoidal waveform (usually 50Hz or 60Hzdepending on the country).

• A coil spins within a magnetic field (or vice versa).
• This induces an oscillating voltage as per Faraday’s Law.
• The output is a sinusoidal waveform (usually 50Hz or 60Hzdepending on the country).

Characteristics:

• Polarity Reversal: Voltage switches between positive and negative at regular intervals.
• Amplitude: Indicates the peak voltage.
• Frequency: Number of cycles per second (Hertz).
• Phase: In multi-phase systems (e.g., 3-phase), voltage waveforms are offsetin time.

In Grid Usage:

• AC voltage is stepped up using transformers for transmission, andstepped down before distribution.
• AC can be easily regulated, switched, and converted using simple oradvanced electronics.

Applicationsof AC Power

AC powers nearly all public and commercial infrastructure. Itsability to be transformed into various voltages makes it versatile for smalldevices and large systems alike.

Special Mention:

Even though devices like computers and EVs operate on DC, theyare typically connected to an AC supply, which is converted to DC viapower adapters or internal circuits.

History of AC Power