piezorezistive

Piezoresistive refers to a property of certain materials to change their electrical resistance when subjected to mechanical strain. This phenomenon is distinct from the piezoelectric effect, which generates an electric charge in response to mechanical stress. In a piezoresistive material, applied stress alters the material's internal atomic structure, which in turn affects the flow of electrons and thus its electrical resistance. This change in resistance can be measured and correlated to the applied stress.

The magnitude of the piezoresistive effect is quantified by the gauge factor, which is the ratio of the relative change in resistance to the applied strain. Materials exhibiting a significant piezoresistive effect include semiconductors like silicon, germanium, and polysilicon, as well as some metals and alloys. The piezoresistive effect in semiconductors is generally much larger than in metals, making them particularly useful for sensor applications.

Piezoresistive sensors are widely used in various applications due to their sensitivity, linearity, and ability to be miniaturized. Common examples include pressure sensors, strain gauges, accelerometers, and load cells. In a typical piezoresistive pressure sensor, a diaphragm deforms under pressure, inducing strain in embedded piezoresistors. The resulting change in resistance is then converted into an electrical signal proportional to the applied pressure. The ability to integrate these sensors onto microelectronic chips has led to their widespread adoption in automotive, industrial, medical, and consumer electronics.