In a schematic, which symbol typically represents a power supply?

The correct representation of a power supply in a schematic is the circle symbol. This symbol is widely used because it visually implies a point source of power and is easily recognizable in circuit diagrams. Circles are conventionally used to denote components such as batteries, power supplies, or other voltage sources, allowing anyone reading the schematic to quickly identify where power is being supplied from.

In terms of the other symbols, while triangles, rectangles, and diamonds have their specific representations in electrical schematics, they do not typically denote power supplies. For instance, triangles often represent operational amplifiers in certain contexts, rectangles might represent passive components like capacitors or resistors, and diamonds can indicate junctions or specific types of devices but not power sources. This standardization helps maintain clarity and consistency in schematic designs across various applications and industries.