A load cell is a sensor used to measure which physical quantity?

• A. Weight
• B. Temperature
• C. Pressure
• D. Humidity

Answer: (A)

A load cell measures weight—the force exerted by gravity on a mass. It achieves this by using a deformable element, such as a metal beam, with strain gauges bonded to it. When a load is placed on the cell, the element deforms slightly and the strain gauges change resistance. This change is converted into an electrical signal that is proportional to the applied force, i.e., the weight. In practice, the output is calibrated to display weight in units like newtons or pounds-force.

Other quantities like temperature, pressure, or humidity rely on different sensing principles (for example, temperature sensors, pressure sensors, or humidity sensors), so a load cell is the appropriate sensor for measuring weight. If needed, weight can be converted to mass by dividing by the gravitational constant.