# Phasors: power, apparent power and theta

Discussion in 'Homework Help' started by paul_alan, Dec 7, 2011.

1. ### paul_alan Thread Starter Member

Nov 5, 2011
43
0
I'm having some trouble with some formulas, maybe someone could help me...A pure capacitance load draws 6A from an 80V source. Determine the power, apparent power and theta. I'm confused as to which value goes on the x-axis and which goes on the y-axis. I want to say current is the x because it's a constant in a series circuit, but i see some phasors are drawn differently. any help is greatly appeciated.

2. ### EL7819 New Member

Apr 15, 2011
20
0
$Total Apparent Power=St=sqrt(Pt^2+Qt^2)$

$P/S=P_{f}$

$P=average power=Watts=VA cos theta$

$S=apparent power=VI=VA$

$Q=reactive power=VAR=VI sin theta$

Last edited: Dec 7, 2011
3. ### t_n_k AAC Fanatic!

Mar 6, 2009
5,448
782
Are you wanting to draw a phasor diagram for this case?