Dielectric Sentence Examples
For constant charges and distances the mechanical force is inversely as the dielectric constant.
This harmonizes with the fact that the real seat of the energy 3f electrification is the dielectric or insulator surrounding the charged conductor.'
Mossotti found a relation between the dielectric constant and the space actually occupied by the molecules, viz.
K= (I +2a)/(I -a), or a=(K-I)/(K+2), where K is the dielectric constant and a the fraction of the total volume actually occupied by matter.
Again, water, the best electrolytic solvent known, is also the body of the highest specific inductive capacity (dielectric constant), and this property, to whatever cause it may be due, will reduce the forces between electric charges in the neighbourhood, and may therefore enable two ions to separate.Advertisement
Clerk Maxwell demonstrated, however, that all electric charge or electrification of conductors consists simply in the establishment of a physical state in the surrounding insulator or dielectric, which state is variously called electric strain, electric displacement or electric polarization.
Under the action of the same or identical electric forces the intensity of this state in various insulators is determined by a quality of them called their dielectric constant, specific inductive capacity or inductivity.
If the two small conducting spheres are placed with centres at a distance d centimetres, and immersed in an insulator of dielectric constant K, and carry charges of Q and Q' electrostatic units respectively, measured as above described, then the mechanical force between them is equal to QQ'/Kd 2 dynes.
This provides us with a definition of a unit of electric force, for it is the strength of an electric field at that point where a small conductor carrying a unit charge is acted upon by unit mechanical force, assuming the dielectric constant of the surrounding medium to be unity.
We must, however, assume that the charge Q is so small that it does not sensibly disturb the original electric field, and that the dielectric constant of the insulator is unity.Advertisement
If the dielectric or separating insulator has a constant K, then the capacity becomes K times as great.
Dielectric constant.-Since all electric charge consists in a state of strain or polarization of the dielectric, it is evident that the physical state and chemical composition of the insulator must be of great importance in determining electrical phenomena.
Cavendish and subsequently Faraday discovered this fact, and the latter gave the name " specific inductive capacity," or " dielectric constant," to that quality of an insulator which determines the charge taken by a conductor embedded in it when charged to a given potential.
The simplest method of determining it numerically is, therefore, that adopted by Faraday.4 Table Dielectric Constants (K) of Solids (K for Air = I).
He constructed two equal condensers, each consisting of a metal ball enclosed in a hollow metal sphere, and he provided also certain hemispherical shells of shellac, sulphur, glass, resin, &c., which he could so place in one condenser between the ball and enclosing sphere that it formed a condenser with solid dielectric. He then determined the ratio of the capacities of the two condensers, one with air and the other with the solid dielectric. This gave the dielectric constant K of the material.Advertisement
The value of the dielectric constant is greatly affected by the temperature and the frequency of the applied electric force.
In general the dielectric constant is reduced with decrease of temperature towards a certain limiting value it would attain at the absolute zero.
Suppose that the dielectric has a constant K, then we must multiply both sides by K and the expression for the energy per unit of volume of the field is equivalent to z DE where D is the displacement or polarization in the dielectric.
The study of electricity he took up in 1746 when he first saw a Leyden jar, in the manipulation of which he became expert and which he improved by the use of granulated lead in the place of water for the interior armatures; he recognized that condensation is due to the dielectric and not to the metal coatings.
In the present case the total dielectric contribution to this current works out to be the change per unit time in the electric separation in the molecules of the element of volume, as it moves uniformly with the matter, all other effects being compensated molecularly without affecting the propagation.Advertisement
The polarization itself is determined from the electric force (P,Q,R) by the usual statical formula of linear type which becomes tor an isotropic medium (.f',g',h') = c2(P,Q,R), because any change of the dielectric constant K arising from the convection of the material through the aether must be independent of the sign of v and therefore be of the second order.
Attempts have been made to co-ordinate this ionizing power of solvents with their dielectric constants, or with their chemical properties.
The electrical resistance is about that of ordinary glass, and is diminished by one-half during exposure by Rntgen rays; the dielectric constant (16) is greater than that which should correspond to the specific gravity.
It has been found, however, that very efficient condensers can be made with compressed air as dielectric. If a number of metal plates separated by small distance pieces are enclosed in an iron box which is pumped full of air to a pressure, say, of 10o lb.
Owing to the variation in the value of the dielectric constant of glass with the temperature and with the frequency of the applied electromotive force, and also owing to electric glow discharge from the edges of the tin foil coatings, the capacity of an ordinary Leyden jar is not an absolutely fixed quantity, but its numerical value varies somewhat with the method by which it is measured, and with the other circumstances above mentioned.Advertisement
One coating of the condenser is formed by one set of tubes and the other by the other set, the air between being the dielectric. Paraffin oil or any liquid dielectric of constant inductivity may replace the air.
Maxwell never committed himself to a precise definition of the physical nature of electric displacement, but considered it as defining that which Faraday had called the polarization in the insulator, or, what is equivalent, the number of lines of electrostatic force passing normally through a unit of area in the dielectric. A second fundamental conception of Maxwell was that the electric displacement whilst it is changing is in effect an electric current, and creates, therefore, magnetic force.
Coupling together these ideas he was finally enabled to prove that the propagation of electric and magnetic force takes place through space with a certain velocity determined by the dielectric constant and the magnetic permeability of the medium.
If we imagine the current in the conductor to be instantaneously reversed in direction, the magnetic force surrounding it would not be instantly reversed everywhere in direction, but the reversal would be propagated outwards through space with a certain velocity which Maxwell showed was inversely as the square root of the product of the magnetic permeability and the dielectric constant or specific inductive capacity of the medium.
An immediate deduction from Maxwell's theory was that in transparent dielectrics, the dielectric constant or specific inductive capacity should be numerically equal to the square of the refractive index for very long electric waves.
At the time when Maxwell developed his theory the dielectric constants of only a few transparent insulators were known and these were for the most part measured with steady or unidirectional electromotive force.
Maxwell made a comparison between the optical refractive index and the dielectric constant of paraffin wax, and the approximation between the numerical values of the square of the first and that of the last was sufficient to show that there was a basis for further work.
Experimental methods were devised for the further exact measurements of the electromagnetic velocity and numerous determinations of the dielectric constants of various solids, liquids and gases, and comparisons of these with the corresponding optical refractive indices were conducted.
On the other hand, the divergence in some cases between the square of the optical refractive index and the dielectric constant was very marked.
After he had educated himself by the study of the phenomena of lines of magnetic force in his discoveries on electromagnetic induction, he applied the same conception to electrostatic phenomena, and thus created the notion of lines of electrostatic force and of the important function of the dielectric or non-conductor in sustaining them.
Since Faraday was well aware that even a good vacuum can act as a dielectric, he recognized that the state he called dielectric polarization could not be wholly dependent upon the presence of gravitative matter, but that there must be an electromagnetic medium of a supermaterial nature.
Faraday had shown that the passage of electrical action involved time, and he also asserted that electrical phenomena are brought about by changes in intervening non-conductors or dielectric substances.
Two patents have been granted on the manufacture of low dielectric loss alumina.
The construction of components, on the micron scale, is by silicon micromachining, electro deposition and thin film metal and dielectric deposition.
The example uses the dielectric constant of water to model the solvent.
This material has a high dielectric constant, similar to a tumor.
For example, DPRO might define the effective dielectric constant in the center of a globular protein.
The crystals are proposed to have 20% lower dielectric than water.
This is a result of the complex dielectric constant which is a measure of the electrical properties of surface materials.
Traps at the front and back gate dielectric interfaces, as well as traps in the body of the dielectric are considered.
Measurement Good Practice Guide No. 25 (High field dielectric properties of piezoelectric materials) Buy Online!
The interconnect capacitance is used as the optimization criteria of low-k dielectric process and the yield impact is reviewed for the concern of manufacturing.
Rolled Aluminum / polyethylene, These capacitors use two long rectangular metal plates, separated by sheets of polyethylene dielectric.
We now know that cold clean Antarctic ice behaves as a low loss dielectric over a wide range of radar frequencies.
The poled microstructure determines the linear elastic, dielectric and piezoelectric moduli.
They were characterized via scanning electron microscopy, complex impedance measurements, electron probe microanalysis and dielectric lifetime testing.
The refractive index, n, is given by the square root of the relative dielectric permittivity, i.e. .
In transparent materials with anisotropic dielectric permittivity, important optical effects can be observed.
In many cases the high Q element can be realized by using a dielectric resonator.
Furthermore, by using high dielectric constant substrates the slot antenna can be used at the various mobile communication bands.
These were actually made between 1885 and 1889, when he was professor of physics in the Carlsruhe Polytechnic. He himself recorded that their origin is to be sought in a prize problem proposed by the Berlin Academy of Sciences in 1879, having reference to the experimental establishment of some relation between electromagnetic forces and the dielectric polarization of insulators.
By placing metal plates on either side of a larger sheet of dielectric or insulator we can construct a condenser of relatively large capacity.
There is a close analogy between the variation of dielectric constant of an insulator with electric force frequency and that of the rigidity or stiffness of an elastic body with the frequency of applied mechanical stress.
Then the quantity E cos OdS is the product of the normal component of the force and an element of the surface, and if this is summed up all over the surface we have the total electric flux or induction through the surface, or the surface integral of the normal force mathematically expressed by JE cos OdS, provided that the dielectric constant of the medium is unity.
The "dielectric constant" of a medium is its specific inductive capacity, and on the electromagnetic theory of light it equals the square of its refractive index for light of infinite wave length (see Electrostatics; Magneto-Optics).
The electrical resistance is about that of ordinary glass, and is diminished by one-half during exposure by RÃ¶ntgen rays; the dielectric constant (16) is greater than that which should correspond to the specific gravity.
Glass is still commonly used as a dielectric because of its cheapness, high dielectric strength or resistance to electric puncture, and its high dielectric constant (see Electro Statics).
James Clerk Maxwell (1831-1879) entered on his electrical studies with a desire to ascertain if the ideas of Faraday, so different from those of Poisson and the French mathematicians, could be made the foundation of a mathematical method and brought under the power of analysis.3 Maxwell started with the conception that all electric and magnetic phenomena are due to effects taking place in the dielectric or in the ether if the space be vacuous.
He formulated the conception, therefore, of electric charge as consisting in a displacement taking place in the dielectric or electromagnetic medium (see Electrostatics).
The surface resistance of the YBa 2 Cu 3 O x thick film was measured using a dielectric resonator technique.
A very small sphere is said then to possess a charge of one electrostatic unit of quantity, when it repels another similar and similarly electrified body with a force of one dyne, the centres being at a distance of one centimetre, provided that the spheres are in vacuo or immersed in some insulator, the dielectric constant of which is' taken as unity.