Which device is commonly used as a position sensor because it produces a variable output?

Which device is commonly used as a position sensor because it produces a variable output?

• A. Limit switch
• B. Potentiometer
• C. Ultrasonic sensor
• D. Bumper switch

Answer: (B)

Position sensing needs a signal that changes smoothly as something moves. A potentiometer is a variable resistor whose resistance changes with the wiper position. When used in a voltage divider, the output voltage at the wiper varies continuously with position, giving an analog, proportional readout of how far something has moved. That continuous, variable output is exactly what you need for precise position feedback. In contrast, limit switches and bumper switches are binary devices: they switch between on and off when a limit is reached, so their output isn’t proportional to position. An ultrasonic sensor measures distance and provides a readout based on that distance, but it doesn’t inherently provide a direct, linear position signal with the simple, continuous mapping a potentiometer offers. That combination of continuous, position-proportional output makes the potentiometer the standard position sensor.

Position sensing needs a signal that changes smoothly as something moves. A potentiometer is a variable resistor whose resistance changes with the wiper position. When used in a voltage divider, the output voltage at the wiper varies continuously with position, giving an analog, proportional readout of how far something has moved. That continuous, variable output is exactly what you need for precise position feedback.

In contrast, limit switches and bumper switches are binary devices: they switch between on and off when a limit is reached, so their output isn’t proportional to position. An ultrasonic sensor measures distance and provides a readout based on that distance, but it doesn’t inherently provide a direct, linear position signal with the simple, continuous mapping a potentiometer offers. That combination of continuous, position-proportional output makes the potentiometer the standard position sensor.