Piezoelectric materials have the special property of producing an electrical voltage in response to an applied force. Usually crystals or ceramics, piezoelectric materials have a variety of uses including sonar, sound detection and high-voltage generation in addition to everyday uses, such as cigarette lighter ignition sources and barbecue-grill igniters.
What Is Piezoelectricity?
Piezoelectricity, derived from the Greek word piezo, meaning to squeeze or press, is an electric charge that accumulates in certain materials such as crystals, ceramics and bone, when a stress or strain is applied to the material. Materials demonstrating the piezoelectric effect also show the opposite effect called converse piezoelectric effect. This means a piezoelectric material becomes deformed, as if undergoing stress, when being exposed to an electrical field. Put briefly, piezoelectric materials create electricity when stress is applied, and become stressed when electricity is applied.
Initially demonstrated in the lab in 1880, the first practical applications for piezoelectric materials were not developed until 1917 during World War I. The very first application was for sonar used to detect submarines with sound waves. After this success, interest in piezoelectric applications grew and by World War II, man-made piezoelectric materials were being constructed and used in aviation radios, filters for radio and television signals and everyday applications, such as small engine igniters.
The piezoelectric effect is found in a number of natural and man-made materials. Commonly used naturally-occurring crystals include quartz, topaz, tourmaline, Rochelle salts and cane sugar. Man-made crystals include the quartz-like langasite and gallium orthophosphate. Common piezoelectric man-made ceramics include barium titanate, lead titanate and lead zirconate titanate, the most common piezoelectric ceramic in use. Other naturally-occurring piezoelectric materials include dry bone, tendons, silk, some woods, enamel, dentin and collagen.
There is a large array of applications for peizoelectric materials, particularly quartz, which can generate thousands of volts of electricity. One of the most common applications of piezoelectricity is in the electric cigarette lighter. Other common applications include sensors on electric guitars like pick-ups and contact microphones, ultrasound machines, sonar wave detection and generation devices, engine management systems in cars, loudspeakers, fuel injectors for diesel engines and quartz clocks.