Building Design and Construction Handbook - Merritt - Ventech!

15.8 SECTION FIFTEEN
or minus. In resistance circuits, the phasor E is indicated by a horizontal line with
the arrowhead at the right:
E�IR
—→
In a circuit that contains inductive reactance, the current I L lags behind the voltage
E by 90�. This is indicated by phasors as follows:
The phasor sum of these voltages is indicated by phasors as follows:
The diagram indicates that
E � IZ cos � (15.14)
L
where � L is the phase angle between voltage and current.
The relation between resistance R and inductance L is indicated by a similar
phasor addition:
The diagram indicates that
R � Z cos � (15.15)
L
In a similar way, capacitive reactance in the circuit is indicated by
and the phasor sum is shown as follows:
The diagrams indicate that