Amplitude

Amplitude, abbreviated as A, is the maximum magnitude or displacement of a periodic wave from its equilibrium or average position.  It is a measure of the extent to which a wave varies from its rest position.

For example, in the case of a simple harmonic wave, like a sine wave, the amplitude is the distance from the equilibrium position to the crest (or trough) of the wave.  In the context of sound waves, amplitude corresponds to the intensity or loudness of the sound.  In electromagnetic waves, such as light, amplitude is related to the brightness of the light.

The amplitude can be described as the maximum value of the displacement function of the wave.  The square of the amplitude is proportional to the energy carried by the wave.

 

Amplitude formula
\( A \;=\;  d \;/\; f \)     (Amplitude) \( d \;=\; A \; f  \) \( f \;=\; d \;/\; A \)
Symbol	English	Metric
\( A \) = Amplitude	\(in\)	\(mm\)
\( d \) = Distance	\(in\)	\(mm\)
\( f \) = Frequency	\(Hz\)	\(Hz\)

   

Amplitude formula
\( A \;=\; s \;/\; sin \; (\omega\; t \;+ \;\phi) \)
Symbol	English	Metric
\( A \) = Amplitude	\(in\)	\(mm\)
\( s \) = Displacement	\(in\)	\(mm\)
\( \omega \)   (Greek symbol omega) = Angular Frequency	\(deg \;/\; sec\)	\(rad \;/\; s\)
\( t \) = Time	\(sec\)	\(s\)
\( \phi \)  (Greek symbol phi) = Phase Shift	\(in\)	\(mm\)