The following is a review of important conclusions that can be derived
from the discussion and examples of the previous sections. The list is
not all-inclusive, but it does emphasize some of the conclusions that
should be carried forward in the future analysis of ac systems.
For series ac circuits with reactive elements:
1. The total impedance will be frequency dependent.
2. The impedance of any one element can be greater than the total
impedance of the network.
3. The inductive and capacitive reactances are always in direct
opposition on an impedance diagram.
4. Depending on the frequency applied, the same circuit can be
either predominantly inductive or predominantly capacitive.
5. At lower frequencies the capacitive elements will usually have the
most impact on the total impedance, while at high frequencies the
inductive elements will usually have the most impact.
6. The magnitude of the voltage across any one element can be
greater than the applied voltage.
7. The magnitude of the voltage across an element compared to the
other elements of the circuit is directly related to the magnitude
of its impedance; that is, the larger the impedance of an
element, the larger the magnitude of the voltage across the
8. The voltages across a coil or capacitor are always in direct
opposition on a phasor diagram.
9. The current is always in phase with the voltage across the
resistive elements, lags the voltage across all the inductive elements by $90^\circ$, and leads the voltage across all the capacitive
elements by $90^\circ$.
10. The larger the resistive element of a circuit compared to the net
reactive impedance, the closer the power factor is to unity.