amplitudo

Amplitudo, often translated as amplitude, is a measure of the extent of an oscillation or wave from its rest position. In mathematical terms, for a sinusoidal wave described by y(t) = A sin(ωt + φ), A represents the amplitude, while ω is the angular frequency and φ is the phase.

In different contexts, amplitude denotes different but related ideas. For mechanical waves, it is the maximum displacement of the medium. In acoustics, larger amplitudes typically correspond to louder sounds because they produce greater pressure fluctuations. In electromagnetism, amplitude refers to the peak strength of the electric or magnetic field. For electrical signals, the amplitude is the maximum voltage or current, and the peak-to-peak amplitude is twice the single-peak value.

The energy carried by a wave in many linear media scales with the square of the amplitude, so increasing amplitude increases energy substantially. In signal processing and instrumentation, amplitude is often compared to the root-mean-square (RMS) value, which reflects the signal’s effective power over time, particularly for non-sinusoidal waveforms.

Beyond classical waves, the term also appears in quantum mechanics and statistics as a probability amplitude, whose modulus squared yields a probability density. The concept is foundational across disciplines, linking the observable size of oscillations to the energy, power, or likelihood associated with the wave or signal. The word “amplitudo” appears in several languages as the equivalent of amplitude.