🔍 Key Concepts

• Root-mean-square (RMS) value and what it represents in AC circuits • How standard AC ammeters and voltmeters are calibrated for sinusoidal waveforms • The difference between peak, average, and RMS values of a sine wave

💭 Think About

• For a pure sine wave, how does the effective heating or power (equivalent DC value) relate to the waveform’s mathematical description? • When an electrician reads 120 V AC on a household voltmeter, is that the peak value, the average over a cycle, or some other standardized value? • Which quantity (peak, RMS, average, maximum) best represents the "effective" value that does the same work as a DC voltage or current?

✅ Before You Answer

• Be clear on the definition of RMS value for a sine wave and why it’s used in power calculations. • Recall how typical commercial AC meters are scaled and calibrated for 50/60 Hz sinusoidal waveforms. • Distinguish between instantaneous maximum/peak and the standardized reading you see on normal AC panel meters.