Basic ac theory - using polar notation?

Discussion in 'Homework Help' started by Steve1992, Sep 25, 2010.

  1. Steve1992

    Thread Starter Senior Member

    Apr 7, 2006
    I like the idea of using polar notation as taught in the AAC e-books - the relative simplicity of using these complex numbers as you would with basic DC theory.

    But does it have its limitations?

    For example:
    A capacitor C is connected in series with 40Ω resistor across a supply of freq. 60Hz. A current of 3A flows and the circuit Z is 50Ω.
    Value of capacitance?

    I cant see a way of using polar notation - the only way I can see to solve this question is to have to draw phasor diagrams, then use trig./pythag. theorems?

  2. Georacer


    Nov 25, 2009
    Polar notation is just another way to express complex numbers. That doesn't mean it is always more convenient than the classic representation of x+yj.
    Polar notation is more convenient for multiplication and division, were the amplitude is multiplied/divided and the phase is added/substracted.
    However, in addition and substraction the cartesian representation is more suitable as you can add/substract the real and imaginary part separately. This is the case in this exercise too.