RMS Full Form in Electrical

What is the full form of RMS?: The full form of RMS in electrical is Root Mean square. The RMS value is used for AC voltage and current. The Root Mean Square, also known as the Quadratic Mean, is the square root of the average of the squares of a set of values. It is a statistical measure of the magnitude of a variable quantity.

Let us discuss some points related to RMS value.

RMS Value Definition:

Definition: The steady current that produces the same amount of heat as the alternating current flowing through a resistor of known resistance for a given period is known as the RMS or effective value of the alternating current. In simpler terms, it is a way to measure the effective power of an AC signal.

In simpler terms, the RMS value is the square root of the average of the squares of instantaneous values.

RMS Formula:


RMS Value of AC Formula:

The formula for calculating the RMS value of an AC signal is;


Relation between Peak(Maximum) Value and RMS Value

The relationship between the peak and RMS values of different AC waveforms is given in the table below.

WaveformRelationship between the peak value and RMS value
SinusoidalIRMS=0.707 Im, VRMS=0.707 Vm
TriangularIRMS=0.577 Im, VRMS=0.577 Vm
SquareIRMS= Im, VRMS= Vm
SawtoothIRMS=0.577 Im, VRMS=0.577 Vm

Here, the full form of IRMS and VRMS are the RMS values of current and voltage, respectively.

The ratio of maximum value and RMS value of AC is called Peak Factor.


The full form of RMS is Root Mean square, and this term is widely used in electrical engineering for alternating voltage and current. You will find its applications in solving electrical circuits.

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