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.
2. A process in which a welder generates a stream of electrons traveling at up to 60 percent of the speed of light as it focuses the beam to a small, precisely controlled spot in a vacuum, and converts the kinetic energy into an extremely high temperature on impact with the piece being worked on.
3. A welding process which takes place in a vacuum.
Heat is produced by a focused electron beam that can produce welds having depth-to-width ratios of up to twenty to one.
Applications include welding of thin metal foils to thicker metal without burning, sealing of metal cans containing uranium fuel elements for reactors, and direct fusion welding of ceramic objects.
The semiconductor target is a pair of silicon diodes, each consisting of two metallic electrodes with a pn (positive-negative) junction under the top contact.
A pn junction or a diode (one way valve) is a pn junction with p-type (positive-type) on one side and n-type (negative-type) on the other side.
When a positive voltage is applied to the p-type side (forward bias), it shrinks and overcomes the depletion zone, causing the current to flow from the p-type to the n-type side. When a negative voltage is applied to the p-type of the diode (reverse bias), it increases the depletion zone and prevents current from flowing.
The amplifier operation is based on the fact that a modulated electron beam can control the current in a reverse-based semiconductor junction.
It is characterized by a circuitry that feeds a portion of the generated energy back into the system to sustain its operation, and by an electron stream that is coupled between the screen and the plate to reduce the effects of the load.2. An oscillator employing a multigrid tube in which the cathode and two grids operate as a conventional oscillator and the electron couples the plate-circuit load to the oscillator.
The anode-circuit load is coupled to the oscillator through the electron stream.
2. Characterized by being relatively opaque to the passage of the electron beam in an electron microscope.
Such an object will appear as a dark area on the viewing screen and photographic prints.
The map is calculated using a Fourier synthesis, a summation of waves of known phase, frequency, and amplitude.2. A three-dimensional representation of the electron density of a molecular structure based on x-ray diffraction data.
2. The diffraction of electrons when they pass through crystalline matter, useful in the study of the structure of materials.
3. An examination of solid surfaces by observing the diffraction of a stream of electrons on the surfaces.
A diffraction is the bending or spreading out of waves; such as, of sound or light, as they pass around the edge of an obstacle or through a narrow opening as when light passes sharp edges or goes through narrow slits and the rays are deflected and produce fringes of light and dark bands.
2. A special evacuated camera equipped with the means for holding a specimen and bombarding it with a sharply focused beam of electrons.
A cylindrical film placed around a specimen and which records the electrons that might be scattered or diffracted by it.
2. A process by which materials that conduct electricity can be removed from a metal by an electric spark.
It is used to form holes with different shapes in materials that have poor machine operations.
2. A curve or line indicating the electron distribution in the different available energy levels of a solid substance.
2. Having the power to attract electrons, and so it is likely to become negatively charged when it is combined with a less electronegative atom or group.
3. Relating to an atom or molecule that tends to draw in electrons from outside the system.
Nonmetals are generally electronegative.
2. The difference in an electrical charge between two points in a circuit expressed in volts of an electrode or as negative with respect to the hydrogen electrode.
A system proposed by Linus Carl Pauling (1901–1994).2. A numerical scale of electronegativities that are based on bond-energy calculations for different elements joined by covalent bonds.