RMS (Root Mean Square)
What does RMS mean?
RMS – Root Mean Square
The term RMS means Root Mean Square and refers to the effective value of a time-dependent electrical quantity, such as voltage or current.
It indicates the DC voltage or current that would produce the same heating effect in a resistor as the alternating quantity under consideration.
Example:
A sinusoidal voltage with a peak value of 325 V corresponds to an RMS value of 230 V. This is exactly the value specified in power engineering or in households (“230 V mains voltage”).
Applications:
- Mains voltage: The specification “230 V” refers to the RMS value of the sinusoidal AC voltage
- Power calculation: In heaters, motors, or light bulbs, the RMS value determines the actual heat generation and power consumption
- Measuring instruments: Multimeters display RMS values by default; for non-sinusoidal signals (e.g. PWM, square wave) True RMS devices are required
- Signal evaluation: In audio and measurement technology, RMS is used to indicate the “effective” strength of a signal