As you have learnt in the text, the two voltages are not
in the same phase Therefore, they cannot be added like ordinary
numbers The two voltages are out of phase by ninety degrees Therefore, the total of these voltages must be obtained using the
Pythagorean theorem:
2
2
R C
R
C
V
V
V
+
=
+
= 220 V
Thus, if the phase difference between two voltages is properly taken
into account, the total voltage across the resistor and the capacitor
is equal to the voltage of the source