| for a time-dependent quantity, positive square root of the mean value of the square of the quantity taken over a given time interval
Note 1 to entry: The root-mean-square value of a periodic quantity is usually taken over an integration interval the range of which is the period multiplied by a natural number.
Note 2 to entry: For a sinusoidal quantity , the root-mean-square value is .
Note 3 to entry: The root-mean-square value of a quantity may be denoted by adding one of the subscripts eff or rms to the symbol of the quantity.
Note 4 to entry: In electrical technology, the root-mean-square values of electric current and voltage are usually denoted I and U, respectively.
Note 5 to entry: The abbreviation RMS was formerly denoted as r.m.s. or rms, but these notations are now deprecated.