أكاديميا - كولنز - معاجم الجيب العلمية - الفيزياء - انكليزي - فرنسي - عربي الحرف ٤_ e

Academia - Collins - Pocket Scientific Dictionaries - Physics - English - French - Arabic Letter 4_ E


electronics
electronic f

electronics . Study of how metals, semiconductors, gases, and vacuums transport current. Electronic engineering generally deals with much smaller currents than electrical engineering. Their circuits tend to be smaller, include a wider range of elements, and do not contain moving parts. Its branches include audio, visual and computer systems.

Microelectronics is concerned with the design and use of integrated circuits.


electroscope
electroscope

Electroscope. A device that allows its user to detect whether an object is charged, in addition to the charge indication. Newer versions of electrometers allow knowing the size of the charge. The leaf electroscope is still very common in education. The central part of it is a thin and light metal leaf mounted on a metal rod. The metal is usually a gold-colored alloy.

The charge given to the head spreads through the metal. The leaf rises because it carries the same charge as the rod, so it is rejected. In normal use, the box is grounded. The angle of the leaf is actually related to the voltage between the case and the rod.

The drawing below shows a negatively charged electroscope (A). If a positively charged body approaches the head, the leaf drops somewhat (b). The same effect occurs if the new body is grounded, but in a lighter way (c).

On the other hand, a nearby negative object makes the leaf rise (D).

See also charging.


electrostatics
electrostatic f

Electrostatics: What is related to static electricity, that is, electrical charges that do not move because they are on insulators such as polyethylene or acetate. (acetate).


element
element m

an item . A single member of a group or system. Thus, the hundred or so chemical elements combine in many thousands of ways to form compounds. In an optical instrument, the lens can actually be a number of lenses connected to each other. They are therefore the elements of the lens. It is also common to use the word to refer to the high-resistance coil in the “electric heater.”


emf
fem

See electromotive force.


emission, electron
Electronic transmission

Electronic version. Electrons escape from the surface in a manner almost similar to evaporation. The electron needs energy to pass through the surface (compare with surface tension). Different types of electronic emission give energy to electrons in different ways.

Thermionic termal emission, shown in Figure (A) below, involves raising the surface temperature. This is the method used in almost all electronic valves (see valve), including the cathode-ray tube.

Photo-emission (b) uses the energy of absorbed waves.
See photo - electric effects.

Secondary emission (c) uses the energy of the absorbed particles. See radiation.