A lighting outlet symbol that is shaped like a circle indicates what type of fixture?

The symbol for a lighting outlet that is shaped like a circle specifically represents an incandescent lighting fixture. This shape is commonly utilized in electrical schematics and blueprints to denote the standard bulb used in incandescent lighting. Incandescent fixtures are often identified by this circular shape due to the form factor of the bulbs themselves, which traditionally have a round appearance.

In other contexts, different types of fixtures may have varying symbols or shapes. For instance, fluorescent fixtures are typically represented with rectangular shapes to indicate the longer form of fluorescent tubes. LED and halogen fixtures may also have distinct symbols that differentiate them based on design and technology. By being aware of these standard symbols, one can easily identify the type of lighting outlet being referred to in technical documents.