Chapter 7 - Sensors

Abstract

Sensors convert information about the environment, such as temperature, pressure, force, or acceleration, into an electrical signal. Silicon's physical properties make it an ideal building material for mechanical devices. Silicon micro mechanical products have several advantages over their conventionally manufactured counterparts such as small size, high performance because of the precise dimensional control in the fabrication, and low costs due to the possibility of mass-scale production. Modern micro mechanics make it possible to produce micro pumps, micro valves, micro-loudspeakers, and microphones. The most common electronic temperature measurement devices that are currently available include the thermocouple, the resistance temperature detector, the thermistor, and the integrated circuit temperature transducer. Silicon wafers are better than metal for pressure sensing diaphragms, as silicon has extremely good elasticity within its operating range. The most popular silicon pressure sensors are piezoresistive bridges. Most pressure sensor manufacturers support three types of pressure measurements: absolute pressure, differential pressure, and gauge pressure. In practical applications, when calculating the total error of a pressure sensor, several defined errors should be used. Pressure sensing is one of the most established and well-developed areas of sensor technology. One reason for its popularity is that it can be used to measure real-world phenomena like flow, fluid level, and acoustic intensities, in addition to pressure.