a pair of equal and opposite electric charges or magnetic poles separated by a small distance
A speaker design which generates equal amounts of sound both forward and backward, with the two sounds being out of phase Dipoles are often used as surround speakers See also Bipole
A molecule which has a definite separation between its center of positive charge and center of negative charge Such a molecule is said to be polar A polar species will be more attracted to a charged species than will a non-polar one
A speaker where the sound emanates from the sides of the monitors, which provides the advantage of additional coverage area A Dipole works well for ambience material but not as well for direct source material
Anything with two equal but opposite electrical charges, such as the positive and negative ends of a polar bond or molecule
A type of antenna with two defined opposing radiating elements, both of the proper length for the frequency of operation, and each forming the counterpoise for the other
an aerial half a wavelength long consisting of two rods connected to a transmission line at the center
a compact source of magnetic force, with two magnetic poles A bar magnet, coil or current loop, if their size is small, create a dipole field The Earth's field, as a crude approximation, also resembles that of a dipole, located near the Earth's center
A type of low-gain (2 2-dBi) antenna consisting of two (often internal) elements
A speaker which radiates sound primarily in opposite directions, 180 degrees out of phase, This creates a null, or area with no sound, to the sides of the speaker Such designs are engineered by using drivers wired out of phase, or by using both sides of a flat driver
An open-back speaker that radiates sound equally front and rear The front and rear waves are out of phase and cancellation will occur when the wavelengths are long enough to "wrap around" The answer is a large, wide baffle or to enclose the driver creating a monopole
Anything with two equal but opposite electrical charges, e g the positive and negative ends of a polar bond or molecule
A pair of equal and opposite electrical charges separated by a small distance A dipole will align itself, if possible, in the presence of other electrical charges according to the attraction of opposite and repulsion of like charges Externally electrically neutral chemical molecules can have a dipole inside E g , water is a triangular molecule with the oxygen at one corner and the two hydrogens at the other two corners The internal charge distribution is such that the hydrogen side has a slight excess of positive charge and the oxygen end is correspondingly negative A dipole is characterized by its "dipole moment," the product of the charge and the separation distance (coulomb times centimeter)
A balanced antenna, usually half a wavelength long and fed (or taken off) at its centre
A type of low gain (2 2 dBi) antenna consisting of two (often internal) elements
an aerial half a wavelength long consisting of two rods connected to a transmission line at the center a pair of equal and opposite electric charges or magnetic poles separated by a small distance
A fundamental form of antenna, comprising a single conductor of length approximately equal to half the wavelength of the carrier wave Provides the basis for a range of other more complex forms of antenna
Two equal electric or magnetic charges of opposite sign, separated by a small distance In the electric case, the dipole moment is given by the product of one charge and the distance of separation This appplies to charge and current distributions as well In the electric case, a displacement of charge distribution produces a dipole moment, as in a molecule
a pair of equal yet opposite electrical charges that are separated by a small distance
A very common structure of magnetic field lines in nature See the figure Many planets, including Earth, have almost dipolar field lines, at least in the near region the planet The "di-" in dipolar refers to the two poles, north and south The overall structure is symmetric about its axis In Earth's case the directions of all of these field lines change over very long periods of time and in fact, the dipole structure has polarity (sign) changes so that its north and south poles change places on a time-scale of hundreds of thousands of years
Pair of equal and opposite electric charges, the centres of which do not coincide. An atom in which the centre of the negative cloud of electrons has been shifted slightly away from the nucleus by an external electric field is an induced electric dipole. When the external field is removed, the atom loses its dipolarity. A water molecule, in which two hydrogen atoms are situated to one side of an oxygen atom, is a permanent electric dipole. The oxygen side is always slightly negative, the hydrogen side slightly positive
An object that has an imbalance between positive charge on one side and negative charge on the other; an object that will experience a torque in an electric field
Tiny magnet with subatomic dimensions, equivalent to the flow of electric charge around a loop. Examples include electrons circulating around atomic nuclei, rotating atomic nuclei, and single subatomic particles with spin. On a large scale, these effects may add together, as in iron atoms, to make magnetic compass needles and bar magnets, which are macroscopic magnetic dipoles. The strength of a magnetic dipole, its magnetic moment, is a measure of its ability to turn itself into alignment with a given external magnetic field. When free to rotate, dipoles align themselves so that their moments point predominantly in the direction of the magnetic field. The SI unit for dipole moment is the ampere-square metre
(physics) a current loop gives rise to a magnetic field characteristic of a magnetic dipole; "An orbiting electron in an atom will have a magnetic dipole moment