Basics
The piezoelectric effects is often encountered in daily life, for example in lighters, loudspeakers and buzzers. In a gas lighter, pressure on a piezoceramic generates an electric potential high enough to create a spark. Most electronic alarm clocks do not use electronicmagnetic buzzers anymore, because piezoelectric ceramics are more compact and more efficient. In addition to such simple applications, piezo technology has recently established itself in the automotive branch. Piezo-driven injection valves in diesel engines require much lower transition times than conventional electromagnetic valves, providing quieter operation and lower emissions.
The term "piezo" is derived from the Greek word for pressure. In 1880 Jacques and Pierre Curie discovered that an electric potential could be generated by applying pressure to quartz crystals; they named this phenomenon the "piezo effect". Later they ascertained that when exposed to an electric potential, piezoelectric materials change shape. This they named the "inverse piezo effect". The first commercial applications of the inverse piezo effect were for sonar systems that were used in World War I. A break through was made in the 1940's when scientists discovered that barium titanate could be bestowed with piezoelectric properties by exposing it to an electric field.
Piezoelectric materials are used to convert electrical energy to mechanical energy and vice-versa. The precise motion that results when an electric potential is applied to a piezoelectric material is of primordial importance for nanopositioning. Actuators using the piezo effect have been commercially available for 35 years and in that time have transformed the world of precision positioning and motion control. |
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Features of Piezoelectric Actuators
- Piezo actuators can perform sub-nanometer moves at high frequencies because they derive their motion from solid-state crystaline effects. They have no rotating or sliding parts to cause friction
- Piezo actuators can move high loads, up to several tons
- Piezo actuators present capacitive loads and dissipate virtually no power in static operation
- Piezo actuators require no maintenance and are not subject to wear because they have no moving parts in the classical sense of the term
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