* Resistance in an AC Circuit means that the voltage and current in the load are in phase.
* Reactance in an AC Circuit means the current waveform may lead or lag behind the voltage wave.
* There are two kinds of reactance: inductive and capacitive. They exist in AC circuits only.
Inductive reactance causes the current to lag the voltage. Capacitive reactance causes the current to lead the voltage.
* In calculations determining reactance, the letter X = Reactance, R = Resistance, XL =Inductive Reactance, Xc = Capacitive Reactance, Z = Impedance
* Inductive reactance is caused by an inductor, which acts as a load. An inductor is a piece of wire that is coiled many times to create a strong magnetic field when current flows through it.
* Capacitive reactance is caused by a Capacitor. A capacitor is a load that contains two pieces of metal facing each other, but not touching. Wires attached to each plate connect the capacitor to the circuit.
* No circuit is 100% resistive, inductive, or capacitive. Circuits are usually a combination of these.
* The combination of resistance, inductance, and capacitance in a circuit is the total opposition to current flow, or impedance (Z).
* When inductive reactance exceeds capacitive reactance, the current will lag behind the voltage.
* When capacitive reactance exceeds inductive reactance, the current will lead the voltage.