R.M.S Value and Average Value

R.M.S Value Or Effective Value

Definition:

The steady current which when flowing through a given resistor fora given time produces the same amount of heat as is produced by the alternating current when flowing through the same resistor for the same time is called R.M.S or effective value of the AC .

In electrical mainly for AC we are always take R.M.S value or Effective values for calculation.

Suppose we say the supply voltage in house 230volts, it means that the R.M.S value of the supply voltage is 230volts. Sometimes we can denote RMS value of voltage by E. As a whole ,we use V (or E) and I for RMS values of A.C voltages and currents respectively.

General formula is

                        R.M.S value=√ Area of squared wave/base

To find RMS value for AC is   =  I_m/√2           (it is only for symmetrical sine waves)

Average Value:

            The average value of  AC is defined as the D.C current which transfers across any circuit the same charge as is transferred by that AC during the same time..

Average value of AC=2/π*I_m

For rectangular wave form RMS value = average value

                        Average value= Area under the curve/base