Reactance and impedance are vital concepts in RLC AC circuits. Reactance refers to opposition to the flow of AC due to inductance or capacitance. Inductors induce inductive reactance, while capacitors exhibit capacitive reactance. Impedance combines resistance, inductive reactance, and capacitive reactance, affecting current flow in the circuit. This handbook deciphers these fundamental concepts, aiding a comprehensive understanding of RLC AC circuits.
Before we begin to explore the effects of resistors, inductors, and capacitors connected together in the same AC circuits, let’s brieﬂy review some basic terms and facts.
Resistance is essentially friction against the motion of electrons. It is present in all con- ductors to some extent (except superconductors!), most notably in resistors. When alternating current goes through a resistance, a voltage drop is produced that is in-phase with the current. Resistance is mathematically symbolized by the letter “R” and is measured in the unit of ohms (Ω).
Reactance is essentially inertia against the motion of electrons. It is present anywhere electric or magnetic ﬁelds are developed in proportion to applied voltage or current, respec- tively; but most notably in capacitors and inductors. When alternating current goes through a pure reactance, a voltage drop is produced that is 90 out of phase with the current. Reactance is mathematically symbolized by the letter “X” and is measured in the unit of ohms (Ω).