why the AC current or vaoltage is represented in rms values ,why DC
current or voltage is represented so.
Thamara:
This is how I have understood it.
Draw a sine wave. Look at it.
Notice how the voltage (or current) starts at zero, peaks (to 1.41
times the RMS value) positive goes to zero and then peaks 1.41 times
RMS negative.
The RMS (Root Mean Square) value of the area within the sine wave can
do the same amount of work (supply the same amount of power etc.) as a
steady state DC voltage (or current) with the same value.
For example suppose a DC value is say a steady unchanging 100.
The equivalent sine wave would start at zero, rise to +141, decline to
zero and then decline to -141.
The RMS value of that rising and falling (alternating polarity voltage
or current) would be the same; i.e. 100.
A better explanation should be in any basic text book.
Have fun.
