piezoelectric materials:
piezoelectric materials are the materials which have the ability to change their shape due to an electric current passing in them, or producing electric current by applying mechanical stresses on them. and this effect of the material is called the piezoelectric effect. this piezoelectric effect can change the volume of the material by a maximum of 4%.

external image piezoeffect.jpgexternal image 220px-SchemaPiezo.gif
History:
the demonstration of the piezoelectric effect came from the term pryoelectric effect which is the response of the material due to temperature change by producing electricity. the pryoelectric effect was first discovered in the mid 18th century by Carl Linnaeus and Franz Aepinus, after that using the knowledge of pryoelectricity both René Just Haüy and Antoine César Becquerel defined a relationship between mechanical stress and electric charge. in 1880 the brothers Pierre Curie and Jacques Curie introduced the first explanation of the direct piezoelectric effect using their knowledge of pryoelectricity, they experimented different crystals like tourmaline, quartz, topaz, cane sugar, and Rochelle salt, and they found that quartz and rochelle salt are the best piezoelectric materials.
Applications:
piezoelectric materials are used as sensors to measure acceleration, strain or force and convert them into electric signal . they are also used as ultrasonic transducers (10 KHZ to 70 KHZ) which is used in imaging and high power applications, in imaging the transducer acts as a sensor and actuator, and in high power applications the transducer sent ultrasonic waves and receive their reflection as in medical applications. moreover piezoelectric materials are used in piezoelectric motors which is based on the change of the shape of the piezoelectric material when a force is applied. furthermore piezoelectric materials are used in more applications like high voltage sources, in lighters or portable sparkers, in the reduction of vibrations also they're used in musical acoustic instruments.
demonstration of the behaviour of piezoelectric materials

External links:
http://www.azom.com/article.aspx?ArticleID=81
http://www.ndt.net/article/platte2/platte2.htm
http://www.americanpiezo.com/knowledge-center/piezo-theory/piezoelectricity.html
References:
http://www.piezomaterials.com/index.htm
http://en.wikipedia.org/wiki/Piezoelectric_material


Made By: Ahmed Mohamed Youssef (1095217)