electro-, electr-, electri-

An instrument used to measure seismic activity; made up of a stack of piezoelectric crystals with intervening metal foils that collect charges produced on the crystal faces when the crystals are strained by pressure from an inertial mass mounted above the stack.

A crystal; such as, quartz, that produces an electric voltage when it is twisted or squeezed, and, conversely, that twists, bends, expands, or contracts when a voltage is applied to it. Commonly used as a transducer to convert mechanical or acoustical signals into electric signals or to regulate frequency in a crystal oscillator.

An instrument used to measure blast pressures resulting from explosions and pressures created in firearms, using a piezoelectric substance that produces a voltage when under pressure.

The hysteretic behavior of a piezoelectric crystal in which the electric polarization depends on the stress history as well as on the mechanical stress applied to the crystal.

1. The ability of crystals to generate a voltage in response to applied mechanical stress.
2. The generation of electricity or of electric polarity in dielectric crystals subjected to mechanical stress, or the generation of stress in such crystals subjected to an applied voltage.
3. Electric currents generated by pressure upon certain crystals; such as, quartz, mica, and calcite.

Piezoelectricity is derived from Greek piezein, "to squeeze" or "to press".

The piezoelectric effect is reversible in that piezoelectric crystals, when subjected to an externally applied voltage, can change shape by a small amount. The deformation, about 0.1% of the original dimension in PZT (lead zirconate titanat or lead zirconium titanate), finds useful applications; such as, the production and detection of sound, generation of high voltages, electronic frequency generation, microbalance, and ultra fine focusing of optical assemblies.

PZT is used to make ultrasound transducers and other sensors and actuators, as well as high-value ceramic capacitors and FRAM chips. FRAM refers to Ferroelectric RAM (FeRAM or FRAM) which is a type of non-volatile computer memory.

FRAM is similar in construction to DRAM, which is currently used in the majority of a computer's main memory, but uses a ferroelectric layer to achieve non-volatility. Although the market for non-volatile memory is currently dominated by Flash RAM, FeRAM offers a number of advantages, notably lower power usage, faster write speed and a much greater number of write-erase cycles.

Any material that generates electrical charges when subjected to a mechanical force.

A field that aims to develop self-powered devices that do not require replaceable power supplies; such as, batteries.

A certain type of piezoelectric material can covert energy at a 100 percent increase when manufactured at a very small size; in this case, about 21 nanometers in thickness.

Many high-tech devices contain components that are measured in nanometers, which is a microscopic unit of measurement representing one-billionth of a meter; a human hair is about 100,000 nanometers wide.

Piezoelectrics are materials; usually, crystals or ceramics, which generate voltage when a form of mechanical stress is applied. They demonstrate a change in their physical properties when an electric field is applied.

Discovered by French scientists in the 1880's, piezoelectrics are not a new concept. They were first used in sonar devices during World War I.

Today they can be found in microphones and quartz watches. Cigarette lighters in automobiles also contain piezoelectrics. Pressing down the lighter button causes impact on a piezoelectric crystal which then produces enough voltage to create a spark and ignite the gas.

While advances in piezoelectrics applications are progressing, piezoelectric work at the nanoscale is a newer endeavor with different and complex aspects to consider; especially, because the size of a hair is much more pliable and susceptible to change from its surrounding environment than larger kinds of materials.

More research is being done to accomplish a self-powering cell phone that never needs to be charged because it will be able to convert sound waves produced by the user into the energy it needs to keep running without batteries.

A semiconductor that exhibits the piezoelectric effect (electric current produced by some crystals and ceramic materials when they are subjected to mechanical pressure); such as, quartz or barium titanate.

A device that uses the interaction between an electric charge and the deformation of a piezoelectric crystal to convert mechanical or acoustical signals into electrical ones, especially such a device used in a microphone.

A sample of piezoelectric material that is attached to electrodes and mounted near some other vibrating element; the piezoelectric sample is used to excite resonant frequencies in the second material.

A polymer film that can convert heat and pressure into electricity.

1. An elementary particle having the same mass and magnitude of charge as an electron but exhibiting a positive charge; a positive electron.
2. A positively charged particle of the same mass and magnititude of charge as an electron; a positive electron.

A method of producing electricity from solar energy by using focused sunlight to heat a working fluid, which in turn drives a turbo-generator.

1. Useful energy that is immediately derived from the sun; for example, a system that collects and uses the heat of the sun to warm a building or to generate electricity.
2. In the larger sense, any energy source that can be ultimately traced to the action of the sun.

A cardiogram which is transmitted electronically to a recording device at a distance from the patient.