Piezoresistive transducers

A quite important parameter for the operation of washing machines is their load. There are several ways to measure the wash load, e.g the force required to rotate the drum/tub/pulsator could be measured and the required amount of water worked out accordingly, or the machine load could be measured by a remote pressure-sensing device with piezoresistive transducers and wireless communication... 

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

Photoelectric Magnetic Piezoresistive transducers Electrical (conductivity) Thermal conductivity... 

Erincipal advantages of piezoresistive transducers are a much higher ridge voltage output and smaller size. Full-scale output voltages of 50 to 100 mV/V of excitation are typical. Some newer devices provide digital rather than analog output. 

Figure 3.141 shows a piezoresistive transducer with a pressure range of 1,500 to 5,000 bar range and a millivolt output. It provides the internal calibration and 0.3% FS accuracy. 

J. T. Rosenberg, Development of a Piezoresistant Transducer to Measure the Stress-Time Output of Small Detonators, Stanford Research Institute Report 1283, Menlo Park, Calif, 1973. 

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