-tron, -tronic, -tronics +

(Greek: a suffix referring to a device, tool, or instrument; more generally, used in the names of any kind of chamber or apparatus used in experiments)

A possible allusion to the Greek instrumental suffix, as in árotron, "plow" as spelled in the U.S. or "plough", as spelled by the British; from the Greek stem aroun, "to plow".

The suffix -tron is the result of the combining form extracted from electron, used with nouns or combining forms, principally in the names of electron tubes (ignitron; klystron; magnetron) and of devices for accelerating subatomic particles (cosmotron; cyclotron); also, more generally, in the names of any kind of chamber or apparatus used in experiments (biotron).

electron-gun-density multiplication, electron gun density multiplication
1. The ratio of the average amount of current density at a given opening to the average current density at the cathode surface.
2. A ratio of the average current density at any specified opening through which the electron stream passes to the average current density at the cathode surface.
electron-hole droplets, electron hole droplets
1. An electronic excitation, observed at low cryogenic temperatures in silicon and germanium, in which an electron-hole Fermi liquid is formed in an unstable condition.
2. A process by which a molecule is excited from a low-lying electronic state to a higher energy electronic state as observed in germanium and silicon at sufficiently low cryogenic temperatures.

It is associated with a liquid-gas phase transition of the charge carriers, and consists of regions of conducting electron-hole Fermi liquid coexisting with regions of insulating exciton gas.

electron-hole pair, electron hole pair
A conduction electron in a conduction band and an accompanying electron hole in the valence band, that result when an electron jumps the gap in an intrinsic semiconductor.
electron-hole recombination, electron hole recombination
A process in which a hole is combined again with an electron within a doped semiconductor (a process where impurities are added to a semiconductor), accompanied by a release of energy, normally in the form of radiation.
1. Relating to devices, systems, or circuits that employ components; such as, vacuum tubes, integrated circuits, or transistors in their design; an electronic sensor.
2. A reference to that branch of science and engineering which deal with the motion, emission, and behavior of currents of free electrons; especially, in vacuum, gas, or phototubes, and special conductors or semiconductors.

This is contrasted with electric, which refers to the flow of large currents in metal conductors.

3. A reference to devices, circuits, or systems using the principle of electron flow through a conductor; for example, electronic control, electronic equipment, electronic instrument, and electronic circuit.
4. Using, or accessed through a computer or computer network; for example, internet electronic banking.

The term electronic is used to refer to equipment, such as television sets, computers, etc., in which the current is controlled by transistors, valves, and similar components and also to the components themselves.

electronic absorption spectrum
Any spectrum produced by the absorption of electromagnetic radiation by ions, atoms, or molecules as a result of electron excitation.
electronic alternating-current voltmeter, electronic alternating current voltmeter
1. A voltmeter consisting of a direct-current milliammeter calibrated in volts and connected to an amplifier-rectifier circuit.
2. A device that measures voltage in amplifier-rectifier circuits.
electronic altimeter, radio altimeter
An instrument that determines the altitude of an object with respect to a fixed level.

The most common type is an aneroid barometer calibrated to show the drop in atmospheric pressure in terms of linear elevation as an airplane, balloon, or mountain climber rises.

It shows height above sea level, but not above such land features as hills, mountains, and valleys.

The radio altimeter, or terrain-clearance indicator, is an absolute altimeter which indicates the actual altitude over water or over terrain, regardless of how uneven it is.

It functions by first sending either continuous or pulse radio signals from a transmitter in an aircraft to the earth's surface.

electronic angular momentum
1. The entire angular momentum including contributions from the spins of all the electrons in an atom.
2. The total angular momentum associated with the orbital motion of the spins of all the electrons of an atom.
electronic article surveillance, EAS (s) (noun); electronic article surveillances (pl)
Simple electronic tags that can be turned on or off to indicate check-out or check-in status of products: When an item is purchased (or borrowed from a library), the electronic article surveillance is turned off.

When someone passes a gate, or door, of a place holding an item with an electronic article surveillance that hasn't been turned off, an alarm sounds.

electronic attitude directional indicator, EADI
A multicolor cathode-ray-tube display of attitude (angle of an aircraft) information, roll and pitch, showing the aircraft's position in relation to the instrument landing system or a very high-frequency omnirange station.

The term omnirange refers to a radio aid to navigation which provides a direct indication of the magnetic bearing (omnibearing) of that station from any direction.

electronic azimuth marker, azimuth marker
1. A line on a radar screen that indicates the bearing of an airborne target.
2. On an airborne radar plan position indicator (PPI) a bright rotatable radial line used for determining the bearing of an aircraft.
electronic balance
1. A micro-balance in which the sample weight is obtained automatically, based on the force produced by current in a coil in a magnetic field.
2. A weighing balance which uses forces produced by known currents to balance unknown currents and, so make unknown weights come to within parts of a microgram.
electronic band spectrum
1. A spectrum characteristic of molecules that consists of bands of spectral lines corresponding to electron transitions accompanied by vibrational or rotational transitions.
2. Bands of spectral lines connected with a change of electronic state of a molecule.

Each band is corresponding to vibrational energies in the initial and final conditions and each band consists of numerous rotational lines.

electronic bearing cursor, electronic bearing marker
1. A line on a radar screen which indicates the bearing of a marine target.
2. A reference to a marine radar set, the bright rotatable radial line on the plan position indicator that is used for the determination of bearing or the calculation of a direction or a geographic position.