What symbol is commonly used in a schematic circuit to represent an AC power source?

In schematic diagrams, an AC power source is typically represented by a specific symbol that is standardized in electrical engineering. This symbol often consists of a sine wave or a combination of a sine wave and parallel lines, indicating that the voltage source alternates in polarity over time, which is a defining characteristic of alternating current (AC).

The selected answer is correct because it identifies the specific representation used in schematics for an AC power source, which is crucial for anyone working with electrical plans to understand. Recognizing this symbol helps electricians and engineers quickly identify the nature of the power sources in a circuit, ensuring proper connections and safety during installation or maintenance.

For reference, the other options do not correspond to the commonly accepted symbol for an AC power source. Instead, they may represent other elements or components, which, while important in circuit schematics, do not fulfill the requirement of signifying an AC power source. Understanding these distinctions is essential for accurate reading and interpretation of electrical schematics.