Also see peak-to-peak .
Alternating current ( AC ) waveforms reach peaks in two directions of polarity or current flow. These peaks are usually of equal amplitude and opposite polarity. However, if a direct current ( DC ) component exists, pk+ differs from pk-. An example of an AC wave with a DC component, showing the pk+ and pk- values, is shown below.
For an AC sine wave without a DC component, the peak amplitude is equal to approximately 1.414 times the root-mean-square amplitude.