🔍 Key Concepts

• Relationship between RMS (root mean square) voltage and average (mean of the rectified) voltage for a pure sine wave • The numerical value of RMS vs average for a sine wave: think of common factors like 0.707 and 1.414 and how they relate to peak and RMS values • Definition of form factor in AC theory (ratio of RMS value to average value)

💭 Think About

• Is the voltmeter scale typically calibrated to show RMS voltage or peak voltage for a standard AC sine wave? • If you know the ratio of RMS to average value (form factor), should you multiply the RMS reading by a number greater than 1 or less than 1 to get the average? • How do the common constants 0.707 and 1.414 usually relate to peak, RMS, and average values in AC circuits?

✅ Before You Answer

• Confirm how average value is defined for a symmetrical sine wave (hint: average over a full cycle is zero, so we normally use the average of the rectified waveform) • Verify the standard form factor for a sinusoidal AC wave and which way the ratio is taken (RMS ÷ average, or average ÷ RMS) • Check that the factor you choose makes sense dimensionally: multiplying the RMS voltmeter reading by this factor should give a smaller or larger value consistent with RMS vs average for a sine wave