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Metals and other solid materials expand upon heating and contract upon cooling. This is an undesirable occurrence in electrical systems. Copper has a low coefficient of thermal expansion for an electrical conducting material. Aluminium, an alternate common conductor, expands nearly one third more than copper under increasing temperatures.
The resistance of a given conductor depends on the material it is made of, and on its dimensions. For a given material, the resistance is inversely proportional to the cross-sectional area. [1] For example, a thick copper wire has lower resistance than an otherwise-identical thin copper wire. Also, for a given material, the resistance is ...
Both are used to create electrically conductive paths through the walls of sealed borosilicate glass containers. Dumet is used for a similar purpose, but is tailored for seals through soda lime and lead alkali silicate glasses. These alloys adhere to lead-tin, tin, and silver solders. Other metals, including copper, molybdenum, nickel, and ...
For example, if A = 1 m 2, = 1 m (forming a cube with perfectly conductive contacts on opposite faces), then the resistance of this element in ohms is numerically equal to the resistivity of the material it is made of in Ω⋅m. Conductivity, σ, is the inverse of resistivity:
Since most conductive polymers require oxidative doping, the properties of the resulting state are crucial. Such materials are salt-like (polymer salt), which makes them less soluble in organic solvents and water and hence harder to process. Furthermore, the charged organic backbone is often unstable towards atmospheric moisture.
Organic conductive materials can be grouped into two main classes: polymers and conductive molecular solids and salts. Polycyclic aromatic compounds such as pentacene and rubrene often form semiconducting materials when partially oxidized. Conductive polymers are often typically intrinsically conductive or at least semiconductors. They ...
A galvanic series is a hierarchy of metals (or other electrically conductive materials, including composites and semimetals) that runs from noble to active, and allows one to predict how materials will interact in the environment used to generate the series.
Doped metal oxides for use as transparent conducting layers in photovoltaic devices are typically grown on a glass substrate. This glass substrate, apart from providing a support that the oxide can grow on, has the additional benefit of blocking most infrared wavelengths greater than 2 μm for most silicates, and converting it to heat in the glass layer.