Phase

Inorder to understand Phase, consider a sine wave. The voltage level of sine waves is related to circular motion. One cycle of a sine wave travels through 360 degrees. Phase shift (also known as delay), describes the difference in timing between two signals. Phase is usually expressed in degrees but a time value may be more appropriate in some circumstances. The phase angle of a sine wave shows how much time it has passed. Two waveforms can have similar frequency and amplitude but they may differ in phase. Two waves may be similar in other ways, but the Phase shift describes the time difference or the delay in the waves.

Phase Shift or Delay