L
VL VR
R
I
VT
I
VL VT
VR
FIGURE 10.5
A series circuit and phasor diagram. The phasor addition these two voltages gives the mag-
nitude and direction VT, which leads the current some angle φ.5 and 10.7(c). 10.6
A series circuit and phasor diagram. 10. The voltage will phase with
the current and will lag the current 90°.7(b), by
the theorem Pythagoras, have:
( )
IZ IX
2 X
2
If now divide throughout I2
we have:
Z X
Z X
2 2
2 2
or
Ω
The phasor diagram can simplified the impedance triangle given in
Fig. From Fig. The phasor addition these
voltages equal the total voltage which, can seen Fig.c. circuit.6, is
lagging the current some angle φ.6, the current will flow through the resistor and capaci-
tor causing voltage drops and VC. Figures 10.6 show the voltage phasors, but we
know that IR, IXL, IXC and IZ, and therefore the pha-
sor diagrams (a) and (b) Fig.
In circuit containing resistor and capacitor connected series as
shown Fig. 10.
.Alternating current theory and electrical machines
199
scale and phase with the current and drawn scale and leading the
current 90°. 10.7 must equal.
The impedance triangle
We have now established the general shape the phasor diagram for a
series a.
C
VC VR
R
I
I
VT VT
VR
FIGURE 10. 10
