For quantum-mechanical amplitude, see
probability amplitude. For the video game of the same name, see
Amplitude (video game).The amplitude is a
nonnegative scalar measure of a
wave's magnitude of
oscillation, that is, the
magnitude of the maximum disturbance in the
medium during one wave cycle.Sometimes this distance is called the peak amplitude, distinguishing it from another concept of amplitude, used especially in
electrical engineering: the RMS or
root mean square amplitude, defined as the
square root of the temporal
mean of the square of the vertical distance of this graph from the horizontal axis. The use of peak amplitude is unambiguous for symmetric, periodic waves, like a
sine wave, a
square wave, or a triangular wave. For an asymmetric wave (periodic pulses in one direction, for example), the peak amplitude becomes ambiguous because the value obtained is different depending on whether the maximum positive signal is measured relative to the mean, the maximum negative signal is measured relative to the mean, or the maximum positive signal is measured relative the maximum negative signal (the peak-to-peak amplitude) and then divided by two.
See more at Wikipedia.org...