تعريفات كهربائية

تعريفات كهربائية

تعريفات كهربائية

Accelerometers : An instrument that measures acceleration or gravitational force capable of imparting acceleration. Accelerometers may also be used for detecting and measuring vibrations.

Actuators : Mechanisms for activating process control equipment by use of pneumatic, hydraulic, or electronic signals.

Buffered : Pertaining to an acid or base solution to which a substance capable of neutralizing the acid or base has been added.

Capacitor : A device that consists of two conductors (such as parallel metal plates) insulated from cach other by a dielectric. A capacitor introduces capacitance (i.e., the ratio of the charge on one of the conductors of a capacitor to the potential difference between the conductors) into a circuit, stores electrical energy, blocks the flow of direct current, and permits the flow of alternating current.

Closed-loop feedback : An automatic control system for an operation or process in which feedback in a closed path or group of paths acts to maintain output at a desired level.

CMOS : Complementary metal oxide semiconductor. A CMOS device is formed by the combination of a pmos (p-type-channel metal oxide semiconductor device) with an nmos (n-type-channel metal oxide semiconductor device. SEE PLANAR DEVICES for definitions of p- and n- type semiconductors.

Electro mechanical : Pertaining to a mechanical device, system, or process that is electrostatically or electromagnetically actuated or controlled.

Epitaxial : Pertaining to semiconductor layers having the same crystalline orientation as the substrates on which they are grown.

Etching : Removal of portions of a layer of conductive material from a usually insulating base through chemical or electrolytic means. In wet etching, the material is dissolved when immersed in a chemical solution. In dry etching, the material is sputtered or dissolved using reactive ions or a vapor phase etchant.

Inertial sensors : Accelerometers that detect a change in inertia (resistance to change in momentum) of the mass or body to which they are attached and convert that change into a useful input signal for an information gathering system.

Integrated circuit : An interconnected array of active and passive elements integrated with a single semiconductor substrate or deposited on the substrate by a continuous series of compatible processes, and capable of performing at least on complete electronic circuit function. Also known as integrated semiconductor.

Micrometer : A unit of length equal to one-millionth of a meter.

Multiplex : (adjective) Being or relating to a system of transmitting several messages, programs, or signals simultaneously on the same circuit or radio frequency channel. (transitive verb) To send (messages or signals) by a multiplex system. (intransitive verb) To multiplex messages or signals.

Photons : quanta (plural of quantum, I.e., very small increments or parcels of electromagnetic radiation (such as light).

Piezoelectric : Having the ability to generate a voltage when mechanical force is applied, or to produce mechanical force when a voltage is applied, as in a piezoelectric crystal.

Piezoelectric : Having the ability to generate a voltage when mechanical force is applied, or to produce mechanical force when a voltage is applied, as in a piezoelectric crystal.

Piezoresistors : Resistors that undergo a change in resistivity when undergoing mechanical stress. See RESISTORS.

Resistors : Devices designed to have definite amounts of electrical resistance; used in circuits to limit current flow or to provide voltage drops.

Semiconductors : Solid crystalline materials whose electrical conductivities are intermediate between that of conductors and insulators, and which are usually strongly temperature-dependent.

Strain gauges : Instruments for measuring the strain, or response to stress, on a structure. The stress is essentially the load on the structure. The load may be dynamic (such as the impact load of a meteor crashing on the Earths surface) or static (such as the load a television set apllies to the floor or stand it is constantly resting upon). In the case of the meteor crashing to the Earth, the strain may be the subsequent crater that is formed. In the case of the television set sitting upon a surface, the strain is the (invisible) pressure that the floor or stand is enduring.

Transducer : Any device or element which converts an input signal into an output signal of a different form; examples include the memsphone, phonograph pickup, loudspeaker, barometer, automobile horn, and doorbell.

Transistor : An active component of an electronic circuit consisting of a small block of semiconducting material to which at least three electrical contacts are made, usually two closely spaced rectifying (i.e., converting an alternating current (ac) to a unidirectional one) contacts and one ohmic (nonrectifying) contact; it may be used as an amplifier, detector, or switch.