Amplitúdu

Amplitúdu is a measure of the extent of displacement or magnitude of an oscillation or wave. In physics and engineering, it is commonly defined as the maximum deviation from an equilibrium position in a periodic motion, or the peak value of a non‑periodic signal. For a sinusoidal wave, the amplitúdu is denoted by A and sets the scale of the oscillation.

Mathematically, a simple sinusoid is written as y(t) = A sin(ωt + φ), where A is the amplitúdu, ω is the angular frequency, and φ is the phase. In space–time form, a traveling wave can be expressed as y(x,t) = A cos(kx − ωt + φ). For non‑stationary signals, an instantaneous amplitúdu A(t) can vary with time, and the slowly changing envelope describes its overall amplitude modulation.

In electrical and acoustic contexts, amplitude refers to the peak value of voltages, currents, or pressure fluctuations. The root‑mean‑square (RMS) value of a sinusoidal signal is V_rms = V_peak/√2. Perception of loudness in acoustics is related to amplitude but not linearly; sound level is commonly expressed in decibels, which reflect logarithmic ratios of amplitude or power.

In the frequency domain, the amplitude spectrum shows the magnitudes of the signal’s frequency components, obtained via Fourier analysis. The peak‑to‑peak amplitude of a pure sine is 2A, while the RMS amplitude is A/√2. Amplitúdu is a fundamental parameter for describing energy transport in waves and for characterizing signals in communication, audio, and optics, including in modulation techniques where amplitude carries information.