gen-briefly-explain-rms-voltage-and-current-and-one-common-misco-f646

Briefly explain RMS voltage and current and one common misconception about it.

# RMS Voltage and Current **RMS (Root Mean Square)** is the equivalent DC value that would produce the same heating effect or power dissipation as an AC signal. **How it's calculated:** Square the instantaneous values over one cycle, find the mean (average), then take the square root. For a sinusoidal AC signal: - **RMS = Peak / √2 ≈ Peak × 0.707** So household "120V AC" actually peaks at ~170V, but delivers power equivalent to 120V DC. ## Common Misconception **"RMS is just the average voltage or current"** ❌ This is incorrect. The simple average of a complete AC cycle is **zero** (positive and negative halves cancel out). RMS is specifically the *square root of the mean of the squares*, which always yields a positive, meaningful value that relates directly to power (P = V²/R). This is why we use RMS instead of simple averaging—it gives us a value that's actually useful for power calculations.