A strain gauge can measure the force of pressure placed on an object or a change in weight.

• A. True
• B. False
• C. Sometimes
• D. Not at all

Answer: (A)

Strain gauges measure mechanical strain—the tiny deformation that occurs in a material when it’s loaded. They’re bonded to a component and, as the component deforms under force, the electrical resistance of the very thin conductor changes. That resistance change is proportional to the strain, and with calibration you can relate it to force.

This lets them sense forces from different sources. If you have a diaphragm, pressure on that surface causes the diaphragm to bend or stretch, producing strain that the gauge detects; from that strain you infer the pressure. Likewise, in a load cell, the weight applied creates force in the supporting structure, causing strain that the gauges pick up and, with geometry and material properties known, you compute the force.

So a strain gauge can measure the force associated with pressure on an object or the force due to weight when used in the appropriate arrangement.