Introduction to Waves

Waveform

Obtained by plotting instantaneous values of a time-varying quantity against time.

Periodic Waveform

A pattern repeats after time. Periodic time is and frequency is .

Alternating Waveform

A waveform that changes in magnitude and direction with time. Is also a periodic waveform.

Sinusoidal Waves

Same as vs (in rad). Also called sine waves or sinusoid.

When is:

• - the wave is said to be leading by
• - the wave is the reference
• - the wave is said to be lagging by

Sinusoidal voltages are be easily generated using rotating machines.

Complex Waveforms

Periodic non-sinusoidal waveforms can be split into its fundamental and harmonics.

Fundamental Waveform

Harmonics

Sine waves with higher frequencies which is a multiple of .

Harmonics are grouped into:

• odd harmonic when is odd.
• even harmonic when is even.