In terms of electrical circuits, what does the symbol 'X' represent?

The symbol 'X' represents reactance in electrical circuits. Reactance is a measure of the opposition that capacitors and inductors present to the flow of alternating current (AC). It is a crucial concept in AC circuit analysis because it affects how the circuit behaves when subjected to alternating voltages and currents.

Reactance is frequency-dependent, meaning that it varies with the frequency of the AC source. For inductors, reactance increases with frequency, while for capacitors, it decreases with frequency. This characteristic allows engineers to design circuits that can filter, tune, or modify AC signals based on their frequency, making reactance an essential factor in many applications, including power distribution and signal processing.

In contrast to reactance, resistance specifically pertains to the opposition to direct current (DC) and is not frequency-dependent. Voltage is a measure of electrical potential, and power describes the rate of energy transfer in a circuit. Understanding these distinctions helps to clarify why 'X' is designated specifically for reactance in circuit diagrams and analysis.