Ac Waveform Phase help please (Degrees or Radians)

Discussion in 'General Electronics Chat' started by jcb19, Feb 25, 2013.

  1. jcb19

    Thread Starter New Member

    Feb 20, 2013
    Hi, could someone give me some help relating to sinusoidal waveform equations and especially the use of radians or degrees?

    I understand that v(t) = VmSin(ωt) or v(t) = √2VSin(ωt) if RMS is used and the same applies for current but V is obviously changed to I etc. I know that ω is 2∏f which is angular velocity so am I right in thinking that radians should always be used when calculating the values of the answers in these cases? My issue seems to be where voltage and current are brought together and say for example the current is said to lead the voltage by 30°, making i(t) = ImSin(ωt + σ). Should radians or degrees be used in this case because if the value of time (t) is anything other than zero, the value of ωt which is in radians will not be equal to zero and hence the value of sin(ωt + σ) will contain both radians and degrees?

    Hope I make sense here, any help would be greatly appreciated.

  2. MrChips


    Oct 2, 2009
    Convert all angles to radians.
  3. jcb19

    Thread Starter New Member

    Feb 20, 2013

    Thanks. So basically I should do everything in radians? The only reason I was confused was because today in my electrical class at uni, we did some calculations using degrees for the phase angle, although this was probably due to the fact we were using t=0 all the time so the calculations were basically just Im*sin(σ)
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    The sin() function works with radians. A human works in degrees.

    That's life.