A common type of sensor used to measure weight is a ____ sensor.

• A. Load cell
• B. Strain gauge
• C. Pressure transducer
• D. Capacitive

Answer: (A)

When you measure weight, you need a device that converts a force (the weight) into an electrical signal. A load cell is designed for this purpose. It usually uses strain gauges bonded to a metal element; when weight applies force, the element deforms slightly, changing the resistance of the gauges. This change is read through a Wheatstone bridge and converted into an electrical signal that is calibrated to weight. The strain gauge is just the sensing element, not a complete weight sensor by itself, so it isn’t used alone to measure weight. A pressure transducer measures pressure, not weight, and capacitive sensors can measure displacement or changes in capacitance but aren’t the standard choice for weighing in most applications.