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The Spitzer resistivity (or plasma resistivity), also called 'Spitzer-Harm resistivity', is an expression describing the electrical resistance in a plasma, which was first formulated by Lyman Spitzer in 1950. [1] [2] The Spitzer resistivity of a plasma decreases in proportion to the electron temperature as /.
Even if the material's resistivity is known, calculating the resistance of something made from it may, in some cases, be much more complicated than the formula = / above. One example is spreading resistance profiling , where the material is inhomogeneous (different resistivity in different places), and the exact paths of current flow are not ...
Reactance is defined as the imaginary part of electrical impedance, and is analogous to but not generally equal to the negative reciprocal of the susceptance – that is their reciprocals are equal and opposite only in the special case where the real parts vanish (either zero resistance or zero conductance). In the special case of entirely zero ...
The electrical resistance of a uniform conductor is given in terms of resistivity by: [40] = where ℓ is the length of the conductor in SI units of meters, a is the cross-sectional area (for a round wire a = πr 2 if r is radius) in units of meters squared, and ρ is the resistivity in units of ohm·meters.
"Degree" in this case can refer to degree Celsius or degree Fahrenheit. When based on Celsius, 0 degrees of frost is the same as 0 °C, and any other value is simply the negative of the Celsius temperature. When based on Fahrenheit, 0 degrees of frost is equal to 32 °F. Conversion formulas: T [degrees of frost] = 32 °F − T [°F]
The mass-to-charge ratio (m/Q) is a physical quantity relating the mass (quantity of matter) and the electric charge of a given particle, expressed in units of kilograms per coulomb (kg/C). It is most widely used in the electrodynamics of charged particles , e.g. in electron optics and ion optics .
Charge carrier density, also known as carrier concentration, denotes the number of charge carriers per volume. In SI units, it is measured in m −3. As with any density, in principle it can depend on position. However, usually carrier concentration is given as a single number, and represents the average carrier density over the whole material.
Absolute thermal resistance is the temperature difference across a structure when a unit of heat energy flows through it in unit time. It is the reciprocal of thermal conductance . The SI unit of absolute thermal resistance is kelvins per watt (K/W) or the equivalent degrees Celsius per watt (°C/W) – the two are the same since the intervals ...