At what value is AC current typically compared to DC current in effectiveness?

The effectiveness of alternating current (AC) compared to direct current (DC) can be evaluated using the concept of root mean square (RMS) values. The RMS value of an AC current provides a measure that expresses the equivalent DC value in terms of power dissipation in a resistive load. For a sinusoidal AC waveform, the RMS value is approximately 0.707 times the peak value of the waveform.

In terms of effectiveness, the RMS value tells us that an AC current can be considered equivalent to a DC current at about 70.7% when discussing the power delivered to a load. This relationship is crucial in electrical engineering as it allows for the direct comparison of AC and DC currents in practical applications, especially in power calculations and circuit analysis.

Thus, the value of 70.7% reflects the inherent properties of sinusoidal waveforms and their ability to convey power in electrical systems, which is why this percentage is commonly recognized in AC versus DC comparisons.