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From Wikipedia
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is a measure of how strongly a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. The SI unit of electrical resistivity is the ohmmetre [Î©m]. It is commonly represented by the Greek letterÏ� (rho).
Electrical conductivity or specific conductance is the reciprocal quantity, and measures a material's ability to conduct an electric current. It is commonly represented by the Greek letter Ïƒ, but Îº (esp. in electrical engineering) or Î³ are also occasionally used. Its SI unit is siemens per metre (SÂ·m^{1}) and CGSE unit is inverse second (s^{â€“1}):
 \sigma = {1\over\rho}.
Definitions
Electrical resistivity Ï� (Greek: rho) is defined by,
 \rho={E \over J} \,\!
where
 Ï� is the static resistivity (measured in ohmmetres, Î©m)
 E is the magnitude of the electric field (measured in volts per metre, V/m);
 J is the magnitude of the current density (measured in amperes per square metre, A/mÂ²).
Most resistors and conductors have a uniform cross section with a uniform flow of electric current and are made of one material. (See the diagram to the right.) In this case, the above definition of Ï� leads to:
 \rho = R \frac{A}{\ell}, \,\!
where
 R is the electrical resistance of a uniform specimen of the material (measured in ohms, Î©)
 \ell is the length of the piece of material (measured inmetres, m)
 A is the crosssectional area of the specimen (measured in square metres, mÂ²).
Explanation
The reason resistivity has the dimension units of ohmmetres can be seen by transposing the definition to make resistance the subject:
 R = \rho \frac{\ell}{A} \,\!
The resistance of a given sample will increase with the length, but decrease with greater crosssectional area. Resistance is measured in ohms. Length over area has units of 1/distance. To end up with ohms, resistivity must be in the units of "ohms Ã— distance" (SI ohmmetre, US ohminch).
In a hydraulic analogy, increasing the diameter of a pipe reduces its resistance to flow, and increasing the length increases resistance to flow (and pressure drop for a given flow).
Resistivity of various materials
 A conductor such as a metal has high conductivity and a low resistivity.
 An insulator like glass has low conductivity and a high resistivity.
 The conductivity of a semiconductor is generally intermediate, but varies widely under different conditions, such as exposure of the material to electric fields or specific frequencies of light, and, most important, with temperature and composition of the semiconductor material.
The degree of doping in semiconductors makes a large difference in conductivity. To a point, more doping leads to higher conductivity. The conductivity of a solution of water is highly dependent on its concentration of dissolved salts, and other chemical species that ionize in the solution. Electrical conductivity of water samples is used as an indicator of how saltfree, ionfree, or impurityfree the sample is; the purer the water, the lower the conductivity (the higher the resistivity). Conductivity measurements in water are often reported as specific conductance, the conductivity of the water at 25 Â°C. An EC meter is normally used to measure conductivity in a solution.
This table shows the resistivity, conductivity and temperature coefficient of various materials at 20 Â°C (68 Â°F)
The effective temperature coefficient varies with temperature and purity level of the material. The 20 Â°C value is only an approximation when used at other temperatures. For example, the coefficient becomes lower at higher temperatures for copper, and the value 0.00427 is commonly specified at 0 Â°C. For further reading: http://library.bldrdoc.gov/docs/nbshb100.pdf.
The extremely low resistivity (high conductivity) of silver is characteristic of metals. George Gamow tidily summed up the nature of the metals' dealings with electrons in his sciencepopularizing book, One, Two, Three...Infinity (1947): "The metallic substa
In physics, thermal conductivity, k, is the property of a material describing its ability to conduct heat. It appears primarily in Fourier's Law for heat conduction. Thermal conductivity is measured in watts per kelvinmetre (WÂ·K^{âˆ’1}Â·m^{âˆ’1}, i.e. W/(KÂ·m). Multiplied by a temperature difference (in kelvins, K) and an area (in square metres, m^{2}), and divided by a thickness (in metres, m), the thermal conductivity predicts the rate of energy loss (in watts, W) through a piece of material. In the window building industry "thermal conductivity" is expressed as the [http://www.energystar.gov/index.cfm?c=windows_doors.pr_ind_tested UFactor] measures the rate of heat transfer and tells you how well the window insulates. Ufactor values generally range from 0.15 to 1.25 and are measured in Btu per hour  square foot  degree Fahrenheit (ie. Btu/hÂ·ftÂ²Â·Â°F). The lower the Ufactor, the better the window insulates.
The reciprocal of thermal conductivity is thermal resistivity.
Measurement
There are a number of ways to measure thermal conductivity. Each of these is suitable for a limited range of materials, depending on the thermal properties and the medium temperature. There is a distinction between steadystate and transient techniques.
In general, steadystate techniques are useful when the temperature of the material does not change with time. This makes the signal analysis straightforward (steady state implies constant signals). The disadvantage is that a wellengineered experimental setup is usually needed. The Divided Bar (various types) is the most common device used for consolidated rock samples.
The transient techniques perform a measurement during the process of heating up. Their advantage is quicker measurements. Transient methods are usually carried out by needle probes.
Standards
 IEEE Standard 4421981, "IEEE guide for soil thermal resistivity measurements", ISBN 0738107948. See also soil thermal properties. [http://ieeexplore.ieee.org/servlet/opac?punumber=2543]
 IEEE Standard 982002, "Standard for the Preparation of Test Procedures for the Thermal Evaluation of Solid Electrical Insulating Materials", ISBN 0738132772 [http://ieeexplore.ieee.org/servlet/opac?punumber=7893]
 ASTM Standard D533408, "Standard Test Method for Determination of Thermal Conductivity of Soil and Soft Rock by Thermal Needle Probe Procedure"
 ASTM Standard D547006, "Standard Test Method for Thermal Transmission Properties of Thermally Conductive Electrical Insulation Materials" [http://www.astm.org/cgibin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D5470.htm?E+mystore]
 ASTM Standard E122504, "Standard Test Method for Thermal Conductivity of Solids by Means of the GuardedComparativeLongitudinal Heat Flow Technique" [http://www.astm.org/cgibin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/E1225.htm?L+mystore+wnox2486+1189558298]
 ASTM Standard D593001, "Standard Test Method for Thermal Conductivity of Plastics by Means of a Transient LineSource Technique" [http://www.astm.org/cgibin/SoftCart.exe/STORE/filtrexx40.cgi?U+mystore+wnox2486+L+THERMAL:CONDUCTIVITY+/usr6/htdocs/astm.org/DATABASE.CART/REDLINE_PAGES/D5930.htm]
 ASTM Standard D271795, "Standard Test Method for Thermal Conductivity of Liquids" [http://www.astm.org/cgibin/SoftCart.exe/DATABASE.CART/REDLINE_PAGES/D2717.htm?L+mystore+wnox2486+1189564966]
 ISO 220072:2008 "Plastics  Determination of thermal conductivity and thermal diffusivity  Part 2: Transient plane heat source (hot disc) method" [http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=40683]
 Note: What is called the kvalue of construction materials (e.g. window glass) in the U.S., is called Î»value in Europe. What is called Uvalue (= the inverse of Rvalue) in the U.S., used to be called kvalue in Europe, but is now also called Uvalue in Europe.
Definitions
The reciprocal of thermal conductivity is thermal resistivity, usually measured in kelvinmetres per watt (KÂ·mÂ·W^{âˆ’1}). When dealing with a known amount of material, its thermal conductance and the reciprocal property, thermal resistance, can be described. Unfortunately, there are differing definitions for these terms.
Conductance
For general scientific use, thermal conductance is the quantity of heat that passes in unit time through a plate of particular area and thickness when its opposite faces differ in temperature by one kelvin. For a plate of thermal conductivity k, area A and thickness L this is kA/L, measured in WÂ·K^{âˆ’1} (equivalent to: W/Â°C). Thermal conductivity and conductance are analogous to electrical conductivity (AÂ·m^{âˆ’1}Â·V^{âˆ’1}) and electrical conductance (AÂ·V^{âˆ’1}).
There is also a measure known as heat transfer coefficient: the quantity of heat that passes in unit time through unit area of a plate of particular thickness when its opposite faces differ in temperature by one kelvin. The reciprocal is thermal insulance. In summary:
 thermal conductance = kA/L, measured in WÂ·K^{âˆ’1}
 thermal resistance = L/(kA), measured in KÂ·W^{âˆ’1} (equivalent to: Â°C/W)
 heat transfer coefficient = k/L, measured in WÂ·K^{âˆ’1}Â·m^{âˆ’2}
 thermal insulance = L/k, measured in KÂ·mÂ²Â·W^{âˆ’1}.
The heat transfer coefficient is also known as thermal admittance
Resistance
When thermal resistances occur in series, they are additive. So when heat flows through two components each with a resistance of 1 Â°C/W, the total resistance is 2 Â°C/W.
A common engineering design problem involves the selection of an appropriate sized heat sink for a given heat source. Working in units of thermal resistance greatly simplifies the design calculation. The following formula can be used to estimate the performance:
 R_{hs} = \frac {\Delta T}{P_{th}}  R_s
where:
 R_{hs} is the maximum thermal resistance of the heat sink to ambient, in Â°C/W
 \Delta T is the temperature difference (temperature drop), in Â°C
 P_{th} is the thermal power (heat flow), in watts
 R_{s} is the thermal resistance of the heat source, in Â°C/W
For example, if a component produces 100 W of heat, and has a thermal resistance of 0.5 Â°C/W, what is the maximum thermal resistance of the heat sink? Sup
From Yahoo Answers
Answers:Check out this diagram. http://www.uq.edu.au/_School_Science_Lessons/3.59ch.GIF Use graphite pencils for the electrodes. Sharpen each end to provide a place to attach the alligator clips. Use a flashlight lamp and the correct number of cells for the lamp.
Answers:just search online for "resistivity table", that is more useful. conductivity is just 1/resistivity. and search for "thermal conductivity table" to get the thermal numbers. here are the ones I have. resistivity Ag 15.9e9 m resistivity Cu 17.2e9 m or 17.2e6 ohmmm resistivity Au 22.14e9 m resistivity Al 28.2e9 m resistivity brass 35e9 m resistivity W 56e9 m resistivity Zn 68e9 m resistivity Fe 100e9 m resistivity Pt 105e9 m resistivity Nichrome 150e8 m thermal conductivity, all in W/mK Silver429 W/mK Copper401 Gold310 Aluminum 250 Beryllium218 Magnesium156 Zinc Zn116 Brass109 Nickel91 Iron80 Platinum70 Tin Sn67 Steel 46 Lead 35 Antimony18.5 Stainless Steel16 Mercury8 .
Answers:Put my Fluke 87 on MHO's and measure it then divided by 1000.
Answers:I answered the other one let me delve into it more... first, quartz can conduct actually, if you've ever owmed a quartz watch or heard of a cesium clock.... If you pass DC voltage into a crystal the crystal....well it gets pissed and vibrates....the output current from the crystal has a AC signature at a known frequency. YOu can then amplify it and pass it through frequency dividers to get 1 hzt, or 5Mhz etc. In wafers, they don't work the same way, the Si doesn't conduct....it's the "board" in which conductive materals are placed to form the logic circuit, but it's all on the surface. Hope this clears it up, chemicals like gemanium, carbon, do all the work, then when the the wafer has all it's channels done it becomes a "back end wafer" and metals are deposited on it to finish up at the very top.
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