In electrical diagrams, what symbol typically represents a motor?

• A. A square with an M inside.
• B. A circle with an M inside.
• C. A circle with a sine wave.
• D. An octagon with an M inside.

Answer: (B)

In electrical diagrams, standard symbols quickly identify devices. A motor is represented by a circle with the letter M inside. The circle marks it as a rotating device, and the M labels it specifically as a motor, so you can tell at a glance that this component converts electrical energy into rotation. This symbol is widely used because it’s clear and unambiguous across schematics and control diagrams. Other shapes aren’t standard motor symbols: a square with M inside isn’t a recognized motor symbol and could suggest a different enclosure or device; a circle with a sine wave inside typically denotes a power source or generator; an octagon with M inside isn’t a common symbol in standard diagrams and would be confusing.