amplitude

In physics, maximum variation of an oscillation from the equilibrium value. In a transverse wave motion, such as an ocean wave, it is the height of a crest (or the depth of a trough). In an electromagnetic wave (which is also transverse), it is the maximum intensity of the electric or magnetic field. For a longitudinal wave, such as a sound wave, amplitude is the maximum distance a particle moves from its resting position. A quiet sound has a lower amplitude and a loud sound has a higher amplitude. For a louder sound, more sound energy enters the ear every second. Amplitude is generally denoted by a.

AM (amplitude modulation) radio broadcasting is a method of transmitting audio-frequency signals. The amplitude of the low-frequency audio signal is made to modulate (vary slightly) the amplitude of a continuously transmitted radio carrier wave of a higher frequency. In this way the modulating signal is imprinted on the carrier wave.

amplitude

In mathematics, the angle in an Argand diagram between the line that represents the complex number and the real (positive horizontal) axis. If the complex number is written in the form r(cos θ + i sin θ), where r is radius and i = √(−1), the amplitude is the angle θ (theta).

The amplitude is also the peak value of an oscillation.