Overload protection on a pressure sensor is similar to overload protection on a load cell. A mechanical stop is inserted to prevent the sensor’s diaphragm from deflecting beyond its elastic limit.

Mechanical overload protection stops are used less often in pressure sensors than in load cells. Bonded, foil strain gauge-based pressure sensors can have mechanical overload protection easily fitted. Silicon-based pressure sensors, because of their minute size and unique deflection/deformation process, have mechanical overload protection fitted less often.

Note: Although silicon-based pressure sensors rarely have mechanical overload protection that comes with a mechanical stop, they exhibit a higher overload capacity than non-mechanically protected, foil strain gauge-based pressure sensors. Silicon-based pressure sensors can sustain a 400% overload capacity. Bonded, foil strain gauge-based pressure sensors, without mechanical stops, can sustain only a 50% (typical) overload capacity.

Thus, a 100 psi silicon-based pressure sensor can sustain a 400 psi applied pressure without incurring damage. A 50,000 psi bonded, foil strain gauge pressure sensor, on the other hand, without a physical overload protection stop, can sustain a 75,000 psi applied pressure before experiencing irreversible damage.