Piezoelectric accelerometer
As with all transducers, piezoelectrics convert one form of energy into another and provide an electrical signal in response to a quantity, property, or condition that is being measured.
Using the general sensing method upon which all accelerometers are based, acceleration acts upon a seismic mass that is restrained by a spring or suspended on a cantilever beam, and converts a physical force into an electrical signal.
When a physical force is exerted on the accelerometer, the seismic mass loads the piezoelectric element according to Newton's second law of motion (
Ceramics use barium titanate, lead-zirconate-lead-titanate, lead metaniobate, and other materials whose composition is considered proprietary by the company responsible for their development.
This method, however, is generally impractical due to the noise that is introduced as well as the physical and environmental constraints posed on the system as a result.
Behind the mystery of the operation of the piezoelectric accelerometer lie some very fundamental concepts governing the behavior of crystallographic structures.
In 1880, Pierre and Jacques Curie published an experimental demonstration connecting mechanical stress and surface charge on a crystal.
The development of the commercial piezoelectric accelerometer came about through a number of attempts to find the most effective method to measure the vibration on large structures such as bridges and on vehicles in motion such as aircraft.
Incidentally, it was Hans J. Meier who, through his work at MIT, is given credit as the first to construct a commercial strain gage accelerometer (circa 1938).
The piezoelectric accelerometer allowed for a reduction in its physical size at the manufacturing level and it also provided for a higher g (standard gravity) capability relative to the strain gage type.
[1] These improvements made it possible for measuring the high frequency vibrations associated with the quick movements and short duration shocks of aircraft which before was not possible with the strain gage types.
Today, piezoelectric accelerometers are used for instrumentation in the fields of engineering, health and medicine, aeronautics and many other different industries.
Piezoelectric accelerometers are used in many different industries, environments, and applications - all typically requiring measurement of short duration impulses.
