Vp×Ip

Vp×Ip refers to the product of the peak (maximum) voltage Vp and the peak current Ip in an electrical signal. Vp is the greatest positive amplitude of the voltage waveform, while Ip is the greatest amplitude of the current waveform. The product Vp×Ip has the dimensions of volt-amperes (VA) and is sometimes used as a rough indication of a source’s peak power capability, but it is not a standard specification in itself.

In the context of power, the instantaneous power is p(t) = v(t) i(t). If voltage and current are sinusoidal and in phase, with v(t) = Vp sin(ωt) and i(t) = Ip sin(ωt), then p(t) = Vp Ip sin^2(ωt). The maximum instantaneous power under this ideal condition is Vp Ip, while the average power over a cycle is Vp Ip/2. For sinusoidal signals in phase, the rms power equals Vrms Irms = (Vp/√2)(Ip/√2) = Vp Ip/2.

It is important to note that Vp×Ip is not a universal limit or specification. Real devices are typically rated by voltage and current levels (often using rms values) or by peak ratings, and the actual power delivered depends on waveform shape and phase difference between voltage and current. Consequently, Vp×Ip is mainly a useful shorthand in certain analyses, rather than a definitive device rating.

See also: power, instantaneous power, peak value, RMS value.