SUMMARY of Series ac Circuits

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 reactance 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 element.
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.