Piezoelectricity from the Greek word "piezo" means pressure electricity. Certain crystalline substances generate electric charges under mechanical stress and conversely experience a mechanical strain in the presence of an electric field.The piezoelectric effect was discovered in some naturally occurring materials in the 1880s. However it was not until the Second World War that man-made polycrystalline ceramic materials were produced that also showed piezoelectric properties. Quartz and other natural crystals found application in microphones, accelerometers and ultrasonic transducers, whilst the advent of the man-made piezoelectric materials widened the field of applications to include sonar, hydrophones, and piezo-ignition systems.Piezoelectric materials are widely used to make various devices including transducers for converting electrical energy to mechanical energy or vice-versa, sensors, actuators, and resonators and filters for telecommunication, control and time-keeping. Piezoelectric materials also act an important role in healthcare applications such as echographic images, new imaging techniques, and use in ultrasonic surgery, miniature sensors and hearing aids and in the transportation industry such as sensor performance devices, actuators, air bag sensors, micro-pumps and micro-motors.Since its discovery, the piezoelectricity effect has found many useful applications, such as the production and detection of sound, generation of high voltages and frequency, microbalances, and ultra fine focusing of optical assemblies. It is also the basis of a number of scientific instrumental techniques with atomic resolution, the scanning probe microscopies such as STM, AFM, MTA, SNOM, etc., and everyday uses such as acting as the ignition source for cigarette lighters and push-start propane barbecues.Piezoelectric devices are a very reliable and inexpensive means of converting electrical energy into physical motion and exhibit a high tolerance to environmental factors such as electromagnetic fields and humidity.Today, piezoelectric applications include smart materials for vibration control, aerospace and astronautical applications of flexible surfaces and structures and novel applications for vibration reduction in sports equipment. Piezoelectric devices are integral components of common devices such as printers, stereos, electric guitars and gas igniting lighters used by millions on a daily basis. The piezoelectric ceramic transducers have also found many important applications in adaptive structures for vibration control and acoustic noise suppression in modern space, civilian and military systems, such as launch vehicles, space platforms, aircraft, submarines and helicopters.