The Full Form of VAF is Voltage Current And Frequency.

The following terms relate to the AC cycle: radians/second, the velocity the loopturns; hertz,  the  number  of  cycles in  one  second;  period, the  time  to  completeone cycle.

Effective value of AC equals effective value of DC.Root mean square (RMS) values equate AC to DC equivalents:

–    I=   0.707 I_max=  Effective Current

–    E     =   0.707 E_max=  Effective Voltage

–    I_av=   0.636 I_max=  0.9 I = Average Current

–    E_av   =   0.636 E_max=  0.9 E = Average Voltage

Phase angle is used to compare two wave forms.   It references the start, or zeropoint,  of  each  wave.    It  compares  differences  by  degrees  of  rotation.    Waveforms with the same start point are “in-phase” while wave forms “out-of-phase”either lead or lag.