Which of the following would be considered an OUTPUT device in a control circuit?

• A. Start pushbutton
• B. Red pilot light
• C. Pressure switch
• D. Float switch

Answer: (B)

In a control circuit, an output device is something that responds to the control logic and produces a visible or tangible result. A red pilot light does just that: when the circuit energizes it, the light comes on to indicate the system’s status. The other items are inputs to the system: a start pushbutton is a human-initiated input, a pressure switch senses pressure and changes state, and a float switch senses liquid level. So the red pilot light is the best example of an output device because it provides a visible indication of the circuit’s state rather than initiating an action.