Piezoelectricity is a type of electricity that occurs when materials possessing piezoelectric properties are exposed to pressure or stress. Examples of these materials are ceramics, also called piezoceramics , and crystals. When force is applied to such materials, a voltage is generated. In many industries, electronic devices possessing piezoelectric properties are very important. They act as transducers. These devices, which are also called piezoelectronics, are used to monitor, detect, test, clean, and measure.
History of Piezoelectricity
In 1880, piezoelectricity was discovered by Jacques and Pierre Curie. The physicist brothers were still both very young at that time. The brothers made the discovery that some crystals produce voltage when they are polarized. The crystals they tested were topaz, cane sugar, and quartz. Perpendicular transverse waves vibrate in a plane during the polarizing process. Horizontally and vertically polarized waves are examples of this.
One of the brothers, Pierre, married Marie Curie several years later. Husband and wife studied radiation and made amazing discoveries about it. Because of this, Pierre and Marie were awarded a Nobel Prize.
Piezoelectric Effect and Converse Piezoelectric Effect
Piezoelectric effect happens when force or pressure is applied to a certain material. The material vibrates when a force or pressure is exerted to it. Crystals, for example, become polarized when they are squeezed, stretched, or twisted. Once polarized, they create voltage. There is a direct proportion between the amount of voltage produced and the amount of applied force.
An opposite effect called converse piezoelectric effect occurs when voltage or emf is applied to the material. The material vibrates and becomes deformed. It shrinks or becomes stretched. The frequency of vibration is the same as the emf frequency. Just to give an example, if an emf of 50 hertz (cycles/second) is applied to a crystal, it will vibrate at 50 cycles/second too.
Piezoelectric effect is present in many different materials. Some of the types of crystals that can produce piezoelectricity are tourmaline, Rochelle salts, and quartz.
Tourmaline is a very durable piezoelectric material. It does not break easily even when voltage is applied to it.
Rochelle salts, unlike tourmaline, easily break when force is applied to them. They are very delicate. Moreover, Rochelle salts are easily affected by voltage.
Quartz is the most popular type of piezoelectric material. Because there is an abundance of quartz, it is popular and cheap.
There are also ceramics that show piezoelectric effect. These ceramics are called piezoceramics. Lead zirconate titanate and barium titanate are two types of piezoelectric ceramics.
Aside from the natural crystals and ceramics mentioned above, piezoelectric effect is also present in synthetic ceramics and crystals.
Piezoelectric effect is also present in some objects that are parts or products of living things. Bones, skin, intestines, aortas, and DNA are piezoelectric. Dentin, which is found in several types of plants and in teeth, can also produce piezoelectricity. Another piezoelectric material is silk.
Uses of Piezoelectric Materials
Piezoelectric materials are very useful. Quartz is used in many watches, RF oscillators, and filters. Tourmaline is usually used in activities that involve high frequencies. In headphones, speakers, and microphones, Rochelle salts are commonly used due to the fact that they are very sensitive to voltage. Piezoceramics are used in ultrasonic transducers and scanning tunneling microscopes (STM). Some microphones also have piezoelectric ceramics. Piezoelectric materials are also used in pressure sensors and some transducers.
- Ultrasonic Sensor
- Ultrasonic Transuder
- Medical Sensor
- Vibration Sensor
- Pressure, sensor
- Compression sensor and others