Phase shift & phase difference
The position of a wave particle of a periodic waveform is known as “Phase” of a waveform. The complete phase of a full cycle of a waveform is 3600.
When two or more waves of the same frequency are interfering in a medium or made to travel in the same path, then the “phase” of waves play an important role to produce the desired output without any noise occurring in it.
Phase can also be defined as “The relative displacement of two waves with respect to each other”.
Related Terms
Phase Difference
The phase difference of a sine wave can be defined as “The time interval by which a wave leads by or lags by another wave” and the phase difference is not a property of only one wave, it’s the relative property to two or more waves. This is also called as “Phase angle” or “Phase offset”.
The phase difference represented by the Greek letter Phi (Φ). The complete phase of a waveform can be defined as 2π radians or 360 degrees.
Leading phase means, a waveform is ahead of another wave with the same frequency and Lagging phase means, a waveform is behind another wave with the same frequency.
Phase quadrature: When the phase difference between two waves is 900 (it may be = + 900 or – 900), then the waves are said to be in ‘Phase quadrature’.
Phase opposition: When the phase difference between two waves is 1800 (it may be = + 1800 or – 1800), then the waves are said to be in ‘Phase opposition.
Phase Difference Equation
The phase difference of sine waveforms can be expressed by below given equation, using maximum voltage or amplitude of the wave forms,
A(t) = Amax×sin(ωt±Ø)
Where
Amax is the amplitude of the measures sine wave
ωt is the angular velocity (radians / Sec)
Φ is the phase angle. (Radians or degrees)
If Φ < 0, then the phase angle of the wave is said to be in negative phase. Similarly, if Φ > 0, then the phase angle of the wave is said to be in a positive phase.
Leading Phase
When two waveforms of the same frequency are travelling along the same axis and one waveform is ahead of another, then it is called ‘Leading phase wave’.
The current and voltage equations for leading phased waveforms are
Voltage (Vt) = Vm sin ωt
Current (it) = Im sin (ωt – Φ)
Where Φ is leading phase angle.
​
Lagging Phase
​
When two waveforms of the same frequency are travelling along the same axis and one waveform is behind of another, then it is called ‘Lagging phase wave’.
The voltage and current equations for leading phased waveforms are
Voltage (Vt) = Vm sin ωt
Current (it) = Im sin (ωt + Φ)
Where Φ is lagging phase angle.