Here’s a party trick (and yes, it works at boring parties). Take any peak voltage, say 325 volts (which is common for 230-volt systems in Europe). Divide by 1.414: that’s about 230 volts RMS. Boom—you’re an electrician for a moment.
If you’re measuring a non-sine wave (like from a dimmer switch), the math gets trickier, but the idea stays the same: RMS captures the effective heating value. That’s why it’s sometimes called the “heating equivalent” voltage.
