Which type of switch opens and closes contacts using a rotary motion?

• A. Push-button switch
• B. Toggle switch
• C. Selector switch
• D. Limit switch

Answer: (C)

Rotary motion is used to select among different contact paths. A selector switch has a rotating actuator—like a knob or key—that you turn to choose a position. As it rotates, internal contacts line up with different terminals, opening some circuits and closing others depending on the position. This makes it ideal for selecting modes or routing signals in a control panel.

Push-button switches operate by pressing a button (either momentary or maintained) and don’t rely on rotation. Toggle switches use a lever that flips between on and off states. Limit switches are activated by the movement of a machine part and change state when a limit is reached. So, a device that opens and closes contacts through a rotating motion is a selector switch.