Sahithyan's S1 — Electrical Fundamentals

AC Theory

Say is alternating as in .

Why AC instead of DC?

Production of AC is less expensive
AC devices are efficient and require less maintenance

Peak value

Maximum instantaneous value. in the example.

Peak-to-peak value

Maximum variation between maximum positive and negative instantaneous values. For a sinusoidal waveform, this is twice the peak value. in the example.

Mean value

Here:

is the starting time of a cycle
is the periodic time

For any symmetric waveform, mean value is .

Average value

Mean value of the rectified version of a waveform.

For symmetric waveforms, half-cycle mean value is taken as the average value.

For sinusoidal waveforms, from the example:

rms value

Aka. effective value. rms value is always used to express the magnitude of a time varying quantity.

For sinusoidal waveforms: