electro-, electr-, electri-

A device that generates electrical energy from light energy, usually as a voltage or current.

1. Pertaining to the electric effects of light or other radiation.
2. Relating to, or produced by, the electrical effects of light, including the emission of electrons, the generation of a voltage, or a change in resistance.

A phenomenon in which electrons are emitted from a material (generally a metal) when it is exposed to light with a given frequency.

The classical concept of light as a continuous wave could not account for this, and it was then explained by Einstein (1905) on the basis that light is a stream of separate particles.

This interpretation, and his subsequent elaboration of it, is said to have formed the basis for much of quantum mechanics.

The electricity produced when light, or other forms of electromagnetic radiation, strike certain materials; such as, cesium, selenium, and silicon.

A galvanic cell in which usable current and voltage are simultaneously produced upon absorption of light by at least one of the electrodes.

The study of electrochemical reactions that are affected or promoted by light.

A material that absorbs incident light to produce current through an external circuit.

a process that uses light energy rather than electrical energy to produce a chemical change in an electrolytic solution.

A proposed process to produce commercial hydrogen, employing the electrolysis (splitting) of water by means of light energy.

An electron emitted from a metallic surface when the latter is illuminated with light, especially with light of short wavelength.

1. Electricity produced by mechanical pressure on certain crystals (notably quartz or Rochelle salt); alternatively, electrostatic stress produces a change in the linear dimensions of the crystal.
2. An electromechanical effect by which mechanical forces acting upon a ferroelectric material can produce an electrical response, and electrical forces can produce a mechanical response.

1. A reference to a crystalline substance the electrical property of which is changed by pressure.
2. Relating to or involving piezoelectricity; such as, piezoelectric plates.

A description of the ability of a solid to generate a voltage when subjected to a mechanical stress, or the ability to generate a mechanical force when subjected to a voltage.

When compressed, some crystalline materials will produce a voltage proportional to the applied pressure; when an electric field is applied across the material, there is a corresponding change of shape.

A reference to the generation of electricity or of electric polarity in dielectric crystals which are subjected to mechanical stress, or the generation of stress in such crystals subjected to an applied voltage.

Any ceramic that exhibits piezoelectric properties.

Japanese manufacturers have shared their piezoelectric discoveries, quickly overcoming technical and manufacturing challenges and creating new markets. Japanese efforts in materials research have created piezoceramic materials competitive with the U.S. materials, but free of expensive patent restrictions.

Major Japanese piezoelectric developments include new designs of piezoceramic filters, used in radios and televisions, piezo buzzers and audio transducers that can be connected directly into electronic circuits, and the piezoelectric igniter which generates sparks for small engine ignition systems (and gas-grill lighters) by compressing a ceramic disc.

Ultrasonic transducers that could transmit sound waves through the air had existed for quite some time, but first saw major commercial use in early television remote controls.

These transducers now are mounted on several car models as an echolocation device, helping the driver determine the distance from the rear of the car to any objects that may be in its path.

A crystal that exhibits the piezoelectric effect; such a crystal is used in electro-audio devices; such as, crystal microphones, speakers, and phonograph pickups.

Piezoelectricity is the ability of certain crystals to generate a voltage in response to applied mechanical stress. The effect is reversible; piezoelectric crystals, subject to an externally applied voltage, can change shape by a small amount. The change is in the range of nanometers, but nevertheless there are useful applications; such as, the production and detection of sound, generation of high voltages, electronic frequency generation, and ultrafine focusing of optical assemblies.

A property known as pyroelectricity, the ability of certain mineral crystals to generate electrical charges when heated, was known of as early as the 18th century, and was named by David Brewster in 1824. In 1880, the brothers Pierre Curie and Jacques Curie predicted and demonstrated piezoelectricity using tinfoil, glue, wire, magnets, and a jeweler's saw.

They showed that crystals of tourmaline, quartz, topaz, cane sugar, and Rochelle salt (sodium potassium tartrate tetrahydrate) generate electrical polarization from mechanical stress. Quartz and Rochelle salt exhibited the most piezoelectricity. Twenty natural crystal classes exhibit direct piezoelectricity.