Phase angle

The phase angle or the phase indicates the current position in the sequence of a recurring task. For sinusoidal waveforms, the phase is the size of the angular function depends directly on ( mathematically as "argument" of the function called ). It therefore has the dimension of an angle.

One can illustrate the course of a harmonic oscillation by a pointer with a constant angular velocity about the origin rotate ( see illustration). If this pointer is projected to one of the two coordinate axes, the end point of the projection leads from the harmonic. The angle enclosed by the pointer with the horizontal axis is the phase angle.

Definitions

For the cosine function

The following variables are defined in the standards:

• The phase angle as the linearly dependent on the time argument of this function,
• Is the angular frequency constant as the frequency or period of time,
• The zero phase angle as the phase angle at the time.

Linked to this is in two equal frequency sinusoidal oscillations

• The phase shift angle and the difference between the phase angle and zero phase angle of the two oscillations. In part, this size is also referred to as " phase difference ", " phase difference " or " phase shift ." Different from the phase angle of the phase shift angle over time a constant.

Applications

• Electrical Engineering: For AC resistors AC voltage and current are shifted against each other in phases.
• For three-phase voltage oscillations in the three lines are shifted by 120 °.