What Does Peak-to-Peak (pk-pk) Mean?
Peak-to-peak (pk-pk) refers to the difference between the highest positive and the lowest negative amplitude in a waveform. For an alternating current (AC) wave in the absence of a direct current (DC) component, the pk-pk amplitude is double the positive peak amplitude. In the case of an AC sine wave having no DC component present, the pk-pk amplitude is equal to approximately 2.828 times the root-mean-square amplitude.
Techopedia Explains Peak-to-Peak (pk-pk)
Peak-to-peak is the amplitude of a waveform that is measured from the crest (top of the waveform) to the trough (bottom of the waveform). Peak-to-peak values are normally used to measure current, power and voltage. The pk-pk amplitude of a signal is sometimes confused with peak amplitude. The two are different, as peak amplitude only gives the maximum positive peak of a waveform, whereas pk-pk amplitude describes the total difference between the top and the bottom of the wave under observation.