Engineering English
RMS
Electrical Engineering · Last updated: July 30, 2026 · How this entry was written
Definition: RMS stands for Root Mean Square, a statistical measure of the magnitude of a varying quantity. For AC signals, it represents the equivalent DC value that produces the same heating effect in a resistor.
Example in context
“The multimeter displayed an RMS voltage of 120 V for the sinusoidal household supply.”
“Multimetre, sinüzoidal ev beslemesi için 120 V RMS voltajı gösterdi.”
Where engineers use it
RMS values are used in AC power calculations for voltage, current, and power. Engineers rely on RMS to specify equipment ratings, measure signal magnitudes, and compute heating effects in conductors.
Synonyms: root mean square, effective value
Antonyms: peak value
Practice: can you use “RMS” at work?
An engineer must size a circuit breaker for a motor load. The motor nameplate shows 10 A RMS. They need to interpret the value correctly and apply safety factors without confusion with peak current.
Show a model answer
“Check the RMS current rating of this cable before proceeding with the design.”
“RMS” in 21 languages
| English | RMS |
|---|---|
| Turkish | RMS |
| French | RMS |
| German | Effektivwert |
| Spanish | RMS |
| Chinese | 均方根值 |
| Arabic | جذر متوسط المربعات |
| Portuguese | RMS |
| Russian | СКЗ |
| Japanese | 実効値 |
| Italian | RMS |
| Vietnamese | RMS |
| Hindi | आरएमएस |
| Thai | ค่าเฉลี่ยกำลังสอง |
| Indonesian | RMS |
| Korean | 실효값 |
| Bengali | আরএমএস |
| Dutch | effectieve waarde |
| Swedish | effektivvärde |
| Finnish | tehollisarvo |
| Ukrainian | середньоквадратичне значення |
Frequently asked questions
What does RMS mean in engineering?
RMS stands for Root Mean Square, a statistical measure of the magnitude of a varying quantity. For AC signals, it represents the equivalent DC value that produces the same heating effect in a resistor. In Electrical Engineering, the term carries a usage-frequency rating of 10/10 in the Engineering English library.
How do you pronounce RMS?
RMS is pronounced /ɑr ɛm ɛs/ (IPA). The Engineering English app plays audio for the term and checks your pronunciation with speech recognition.
How is RMS used in a sentence?
Example from an engineering context: “The multimeter displayed an RMS voltage of 120 V for the sinusoidal household supply.”
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