Wiki
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 sinusoidalwave, allowing for smooth and consistent power delivery.
- Frequency: Commonly 50 Hz (cycles per second) inmost of the world, 60 Hz in regions like North America.
- Voltage: Constantly rises and falls, changingpolarity at each half-cycle.
Callout: The Current That Reverses Direction—But Never DropsPower
AlternatingCurrent (AC) reverses direction many times per second (typically 50 or 60times), but devices don’t lose power because the energy delivered is measuredby the root mean square (RMS) value of the waveform, not its direction.The voltage rises and falls in a smooth sine wave, and although the directionof flow changes, the amount of usable power remains constant. This iswhy AC can efficiently power appliances, lights, and motors—even whilecontinuously changing direction.
How Does AC Work?
AC works on the principle of electromagnetic induction, discovered by Michael Faraday. An alternator (AC generator) spins a coil of 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 60Hz depending 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 offset in time.
In Grid Usage:(give link for ac grid wiki)
- AC voltage is stepped up using transformers for transmission, and stepped down before distribution.
- AC can be easily regulated, switched, and converted using simple or advanced electronics.
Applications of AC Power
AC powers nearly all public and commercial infrastructure. Its ability to transform into various voltages makes it versatile for small devices and large systems alike.
