Which of the following is NOT an example of an input device?

• A. Electric motor
• B. Switch
• C. Sensor
• D. Pushbutton

Answer: (A)

Input devices are components that send information into the control system by converting physical events or states into electrical signals the controller can read. A switch and a pushbutton are classic manual input devices because they directly generate a signal when you interact with them, telling the system to start, stop, or change state. A sensor fits here as well, since it measures a physical quantity (like temperature, light, or position) and converts that measurement into a signal for the controller to process. An electric motor, however, is an actuator. It receives a control signal and performs work by producing mechanical motion, rather than providing information to the controller. So the motor is not an input device.