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The siemens (symbol: S) is the unit of electric conductance, electric susceptance, and electric admittance in the International System of Units (SI). Conductance, susceptance, and admittance are the reciprocals of resistance, reactance, and impedance respectively; hence one siemens is equal to the reciprocal of one ohm (Ω −1) and is also referred to as the mho.
The commonly used standard cell has a width of 1 cm [clarify], and thus for very pure water in equilibrium with air would have a resistance of about 10 6 ohms, known as a megohm. Ultra-pure water could achieve 18 megohms or more. Thus in the past, megohm-cm was used, sometimes abbreviated to "megohm".
where is the length of the conductor, measured in metres (m), A is the cross-sectional area of the conductor measured in square metres (m 2), σ is the electrical conductivity measured in siemens per meter (S·m −1), and ρ is the electrical resistivity (also called specific electrical resistance) of the material, measured in ohm-metres (Ω ...
10 3 to 10 4: 10 −4 to 10 −3 [46] Deionized water [q] 1.8 × 10 5: 4.2 × 10 −5 [47] Ultrapure water: 1.82 × 10 5: 5.49 × 10 −6 [48] [49] Glass: 10 11 to 10 15: 10 −15 to 10 −11 [21] [22] Carbon (diamond) 10 12 ~ 10 −13 [50] Hard rubber: 10 13: 10 −14 [21] Air: 10 9 to 10 15 ~ 10 −15 to 10 −9 [51] [52] Wood (oven dry) 10 ...
If this convention is used, then the values are in the same range as monovalent ions, e.g. 59.5 S cm 2 mol −1 for 1 / 2 Ca 2+ and 80.0 S cm 2 mol −1 for 1 / 2 SO 2− 4. [4] From the ionic molar conductivities of cations and anions, effective ionic radii can be calculated using the concept of Stokes radius.
As quoted in an online version of: David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition.CRC Press. Boca Raton, Florida, 2003; Section 4, Properties of the Elements and Inorganic Compounds; Physical Properties of the Rare Earth Metals
(5.45) The overdrive voltage (sometimes known as the effective voltage) is customarily chosen at about 70–200 mV for the 65 nm process node (I D ≈ 1.13 mA/μm × width) for a g m of 11–32 mS/μm. [3]: p. 300, Table 9.2 [4]: p. 15, §0127 Additionally, the transconductance for the junction FET is given by
where TDS is expressed in mg/L and EC is the electrical conductivity in microsiemens per centimeter at 25 °C. The conversion factor k e varies between 0.55 and 0.8. [5] Some TDS meters use an electrical conductivity measurement to the ppm using the above formula. Regarding units, 1 ppm indicates 1 mg of dissolved solids per 1,000 g of water. [6]