Equation of Sinusoidal Alternating Quantity:

The sinusoidal alternating current is written as

                                                     i = I_m  sin ωt

Likewise, we may write for voltage

              v = V_m  sin ωt

where  i, ν = Instantaneous value of current and voltage

I_m, V_m = Maximum values

ω = 2πf [f = frequency in Hz]

= 2π/ T [T = Time period in sec]

Phase of any alternating quantity illustrates the position of wave at any time after it has passed through the zero position of reference.