AC Phasor and Sinusoid
A compact view of how a rotating AC phasor maps to instantaneous sinusoidal voltage.
AC Phasor and Sinusoid
A compact view of how a rotating AC phasor maps to instantaneous sinusoidal voltage.
Control visualization - the phasor rotates automatically; pause, change speed, or scrub the phase to see the sinusoid projection.
What it shows
A phasor is a rotating vector of fixed length (the amplitude Vm) spinning at the system frequency. Its vertical projection at any instant equals the instantaneous voltage, v(t) = Vm·sin(θ). As the phasor sweeps from 0° to 360°, the diagram traces out one full cycle of the AC sinusoid — the rotating picture and the time-domain wave are the same information in two views.
Why it matters for BESS
Inverters, transformers, and grid studies all reason about AC quantities as phasors. Holding amplitude and phase in your head as a single rotating vector is what makes power-factor, reactive-power, and ride-through analysis tractable — every other electrical visual in this library builds on this projection.
Frequently asked
- What is a phasor?
- A phasor is a complex number (magnitude and angle) that represents a sinusoidal quantity of known frequency. The magnitude is the waveform amplitude and the angle is its phase; rotating it and reading the vertical projection reconstructs the instantaneous value.
- Why use phasors instead of time-domain waveforms?
- At a single steady-state frequency, phasors turn differential equations into algebra. Adding two AC signals becomes vector addition, and phase relationships (leading/lagging) are read directly as angles.