electro-, electr-, electri-

(Greek > Latin: electric, electricity; from amber, resembling amber, generated from amber which when rubbed vigorously [as by friction], produced the effect of static electricity)

Electronics in our lives consists of numerous tools

Equipment which we use everyday relies on electronics to function including calculators, car controls, cameras, washing machines, medical scanners, mobile telephones, radar systems, computers; as well as many other applications or devices which are listed in this unit.

photoelectrolysis, photoelectrolytic
a process that uses light energy rather than electrical energy to produce a chemical change in an electrolytic solution.
photoelectrolytic (hydrogen) production
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.
piezo effect, piezoelectric effect
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.

piezoelectric ceramic
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.

—Compiled from information presented by

piezoelectric crystal
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 has the function of certain crystals to generate a voltage in response to applied mechanical stress.

The result is reversible in that the piezoelectric crystals, subject to an externally applied voltage, can change shape by a minimal amount.

The change is in the degree of nanometers although there are useful applications; such as, the production and detection of sound, the generation of high voltages, electronic frequency generation, and the ultrafine focusing of optical assemblies.

A characteristic known as pyroelectricity, which is the ability of certain mineral crystals to generate electrical charges when heated, was determined 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. There are twenty known natural crystal classes that exhibit direct piezoelectricity.

—Essentially compiled from information presented by
piezoelectric crystals
1. The production of electricity or electric polarity by applying a mechanical stress to certain crystals.
2. The generation of an electric charge in certain nonconducting materials, such as quartz crystals and ceramics, when they are subjected to mechanical stress including pressure or vibration, or the generation of vibrations in such materials when they are subjected to an electric field.

Piezoelectric materials exposed to a fairly constant electric field tend to vibrate at a precise frequency with very little variation, making them useful as time-keeping devices in electronic clocks, as used in wristwatches, and computers.

piezoelectric detector
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.
piezoelectric element
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.
piezoelectric gauge
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.
piezoelectric hysteresis
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.
piezoelectric material
Any material that generates electrical charges when subjected to a mechanical force.
piezoelectric semiconductor
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.
piezoelectric transducer
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.

The references or sources of information for compiling the words and definitions in this unit are listed at this Electronic Bibliography page or specific sources are indicated when they are appropriate.

A cross reference of word units that are related, directly and/or indirectly, with "electricity": galvano-; hodo-; ion-; piezo-; -tron; volt; biomechatronics, info; mechatronics, info.