Ham Amateur Radio Technician Practice Exam 2026 – The Complete All-in-One Guide to Exam Success

The RMS (Root Mean Square) value of an AC signal is the correct answer because it is specifically designed to represent the equivalent DC power that would be dissipated in a resistor. When calculating power in resistive circuits, we use the formula \( P = \frac{V^2}{R} \), where V represents the voltage.

For a DC voltage, the average value and the RMS value are the same since the current is constant. However, with AC signals, the voltage and current continuously vary, and the RMS value takes these variations into account. It does so by effectively averaging the instantaneous values of the voltage over a complete cycle and provides a single value that equates to the direct current (DC) equivalent in terms of thermal dissipation in a resistor.

The average value of an AC signal does not produce the same power dissipation as a DC voltage, since it won't account for the full cycles of the waveform. The peak value only refers to the maximum instantaneous voltage, which is also not equivalent to the power dissipated in a resistor. The peak-to-peak value indicates the total voltage swing from the highest positive to the lowest negative point in an AC waveform, but once again does not relate directly to resistive power dissipation