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# AC BASIC AND NETWORKS

How to Understood of Determination of Maximum value and Frequency from EMF or Current Equations ?

The equation for the instantaneous values of Emf is given as

e = Emax sin 2Ï€ft = Emax sin 2Ï€ft
From the above equation we observe that

i) the maximum value of an alternating EMF is given by the Coefficient of the sine of the time angle.
ii) the frequency is given by Coefficient of time t divided by 2Ï€

Coefficient of time t
i.e.,   f  =  ------------------------------
2Ï€

Similarly we can also find the maximum value and Frequency of the current from the equation of instantaneous values of current.

Form Factor and peak Factor.

Form factor is defined as the ratio of effective value to the average or mean value of a periodic wave.

Mathematical form factor is given by the relation
Effective Value
Form Factor =  -----------------------------
Average value

The value of form factor for perfect sinusoidal, half- wave rectified full wave rectified, rectangular and triangular wave alternating Current are 1.11, 1.57, 1.11, 1 and 1.16 respectively.
Peak or crest or amplitude factor of a periodic wave is defined as the ratio of maximum or peak to the effective or rms value of the wave.

Maximum value
i.e., Peak Factor, Kp = -----------------------
Effective Value

The value of peak of crest factor for Perfect sinusoidal , half wave rectified, full wave rectified, rectangular and triangular wave alternating Current are √2, 2.0, √2, 1 and
√3 respectively.

Phase and phase Angle

By phase of alternating Current is meant the function of the Time period of that alternating Current that has elapsed since the current last passed through

 Phase and phase Angle

the zero position of reference. The phase Angle of any quantity means the angle the phaser representing the quantity makes with the reference line ( Which is taken to be at zero degrees or radians). For example the phase Angle of Current I2 in fig. Is (-Î¦).