What type of waveform would be indicated by a wavy red line in an illustration?

A wavy red line in an illustration typically represents an unrectified alternating current (AC) waveform. Unrectified AC is characterized by its sinusoidal shape, indicating that the current flows in both directions, which is consistent with alternating current's behavior in electrical circuits. This waveform shows the variation in voltage and current over time, alternating between positive and negative values, reflecting the nature of AC where the direction changes periodically.

In contrast, direct current (DC) is represented by a flat, straight line, indicating a constant voltage in one direction. Rectified AC would show a waveform that is only positive, often appearing as a series of peaks or pulses, demonstrating the effect of components like diodes that allow current to flow in only one direction. Pulsating direct current, although it shows variation, is usually a modified version of DC and would not appear as a continuous wavy line but rather as a series of spikes or levels indicating the pulsing nature.

Thus, the wavy red line effectively captures the characteristics of an unrectified AC waveform, making this the correct interpretation.