Alternating current and Alternating EMF


  • An alternating current is one whose magnitude changes sinusoidal with time .Thus alternating current is given by
    Where,
    i0=current amplitude or peak value of alternating current
    If T is the time period of alternating current and f is the frequency, then
    Where ω is called angular frequency of A.C and φ is known as phase constant
  • Instead of sine function AC can also be represented by cosine function and both representation leads to same results. We will discuss circuits with sine representation of A.C
  • Figure below shows the variation of A.C with time
  • Complete set of variations of the current in one time period T is called cycle
  • The emf or voltage whose magnitude changes sinusoidal with time is known as alternating emf and is represented by
    where V0 is the peak value of alternating current. 

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