Piezoresistant gauges

Fig. 3.7. The time periods over which significant developments are reported in the literature for the various piezoelectric and piezoresistant gauges are shown. It should be noted that the development period for development of such detectors is a minimum of 10 yr and possibly more typically 15 yr.

The development of piezoresistant gauges provides a counterexample in that early work was based on empirical study of responses based on simple... 

Piezoresistive Sensors. The distinction between strain-gauge sensors and pie2oresistive (integrated-circuit) sensors is minor. Both function by measuring the strain on an elastic element as it is subjected to pressure. A pie2oresistive transducer is a variation of the strain gauge that uses bonded... 

Measurements from stress gauges, assuming equal accuracy and time resolution, are equivalent to measurements from particle velocity gauges in exploring a material s equation of state. Both piezoresistive and piezoelectric techniques have been used extensively in shock-compression science. 

Electric sensing devices (strain gauges, piezoresistive transducers, and piezoelectric transducers)... 

The principle of the resistance strain gauge 2 0 is that the electrical resistance of a conductor will change when it is stretched or compressed due to the consequent variation in its physical dimensions. There is an additional effect called the piezoresistance which is the relation between the resistivity p of the material and the mechanical strain. The resistance R of a conductor of area of cross-section A and length x is given by ... 

Semiconductor strain gauges have a much larger piezoresistance effect leading to gauge factors of between 100 and 175 for P type material and between -100 and -140 for N type material. These consequently are much more sensitive to changes in strain than the metal resistance types. On the other hand, they are affected to a greater extent by variations in temperature. 

Kato et al. [26] directly observed the shock-pressure history by using an in-material piezoresistive carbon gauge to study the ice Hugoniot in detail below 1 GPa. They found that the HEL (Hugoniot Elastic Limit) of ice was between... 

B-doped p-type diamond films are known to exhibit piezoresistivity. Namely, the resistance increases under compressive stress [418]. The piezoresistivity is expressed by the gauge factor K, which is defined by ... 

Use was made of a piezoresistive strain gauge array to measure the stress distribution on the surface of the die. A beam bending apparatus was used to study the importance of the thermoviscoelastic properties of the molding compound. The strain gauge allowed for the study of the effects of thermal shock testing. 

The various mechanisms contributing to piezoresistivity mentioned above are closely related to the symmetry of the crystal and to the distortion by the applied strain. One consequence is that the change in the resistance is different when the strain is applied parallel (longitudinal) and perpendicular (transverse) to the electrical current. In analogy to Eq. (1), this can be accounted for by longitudinal (K(,, ) and transverse (Kgf.i) gauge factors ... 

Interest has been shown in the piezoresistance properties of Magnus Green Salt. As in the case for Ir(CO)2(acac), a high hydrostatic gauge factor is observed (25). Materials with a smaller metal-metal interaction, for example [M(NHs)4] [M CU] (M, M = Pd, Pt), exhibit smaller pressure effects. 

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