A pressure transducer is a transducer that converts pressure into an analog electrical signal. There are various types of pressure transducers, such as a capacitive pressure transducer, digital output pressure transducer, voltage/current output pressure transducer, and many others. However, in all types of pressure transducers the conversion of pressure into an electrical signal is achieved by the physical deformation of the diaphragm of the pressure, which then produces an electrical resistance change proportional to the pressure.
The History of Pressure Transducers
As far back as Galileo Galilei, scientists have been trying to measure pressure. For almost the next three hundred years, scientist would make discoveries that helped inform their understanding of pressure measurement. However, it wasn’t until 1930, with the invention of an unbonded strain gauge by Roy Carlson, a civil engineer, that big strides were made with pressure transducer technology.
1930: Roy Carlson designed the first unbonded wire strain gauge to measure the strain inside a concrete structure.
1938: Arthur Ruge, Massachusetts Institute of Technology, and Edward Simmons, California Institute of Technology, independently but simultaneously develop a process for a bonded wire strain gauge. The two men ended up applying for a patent together.
1952: Foil strain gauges were invented by Peter George Scott Jackson of Saunders-Roe Ltd. Foil strain gauges provided advantages over bonded wire gauges, including better heat dissipation, better thermal stability, better reproducibility, and lower production costs.
1954: The capacitive pressure transducer was developed by Carl Spaulding. These sensors provided a way to measure very small pressures with sufficient accuracy.
1960s: The first thin-film transducers with good stability and low hysteresis were developed. The technology remains in use today for measuring high pressure. Meanwhile, silicon diaphragm and silicon sensor patents were also developed in the late 1960s by Art Zias and John Egan of Honeywell Research Center.
1973: William Polye of Bendix Corporation designed a capacitive transducer using quartz. This made it possible to measure lower pressure ranges.
1979: Robert Bell of Kavlico built on the capacitive transducer technology to replace the quartz body with a ceramic one. This design remains commonly used today.