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Basic Theory

AC Basics

AC Basics Definition Alternating current is current whose magnitude and direction change periodically. Basic Parameters Frequency (f) Number of changes per seco…

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ACFrequencySine waveBasics

AC Basics

Definition

Alternating current is current whose magnitude and direction change periodically.

Basic Parameters

Frequency (f)

Number of changes per second, unit Hz

Period (T)

T = 1/f

Angular Frequency (ω)

ω = 2πf

Sinusoidal AC

u = Um × sin(ωt + φ)
  • Um: Amplitude
  • ω: Angular frequency
  • φ: Initial phase
  • RMS Value

    RMS = Amplitude / √2 ≈ Amplitude × 0.707

    Example: Peak value of 220V AC

    Peak = 220 × √2 ≈ 311V