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Topic: Resistance thermometer

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Constantan

Thermocouple

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	Thermometer - MSN Encarta
		The modern alcohol and mercury thermometers were invented by the German physicist Gabriel Fahrenheit, who also proposed the first widely adopted temperature scale, named after him, in which 32° F is the freezing point of water and 212° F is its boiling point at standard atmospheric pressure.
		This phenomenon is the basis of the resistance thermometer in which a constant voltage, or electric potential, is applied across the thermistor, or sensing element.
		A mercury-in-glass clinical thermometer, for example, is a maximum-reading instrument in which a trap in the capillary tube between the bulb and the bottom of the capillary permits the mercury to expand with increasing temperature, but prevents it from flowing back unless it is forced back by vigorous shaking.
	encarta.msn.com /encyclopedia_761574061/Thermometer.html (1133 words)

	Carotid thermodilution catheter - Patent 4240441
		The size and the resistance of heating coil 12 and platinum resistance thermometer 15 are determined in part by the size of the catheter.
		For the present invention, the length of heating coil 12 varies from 4-5 centimeters (21/2 centimeters for pediatrics) and the range of the length of resistance thermometer 15 is 3 to 4 centimeters (2 centimeters for pediatrics).
		The resistance (and impedance) of heating coil 19 is also kept at a predetermined level by reducing or increasing the number and length of the wires used in parallel, to suit the range of blood to be measured.
	www.freepatentsonline.com /4240441.html (4154 words)

	Thermometer Summary
		A gas thermometer has the column filled with gas at a low pressure and there is a weight at the top of the column to maintain a constant pressure.
		Réaumur's thermometer was remarkable in that he devised an 80-degree temperature scale based upon the freezing and boiling points of water--the same points that, years later, would become the basis for the more widely accepted scales of Celsius and Fahrenheit.
		Thermometers may be low-cost models that may be found in a medicine cabinet, or high-tech models used in research and engineering.
	www.bookrags.com /Thermometer (2004 words)

	Training (Site not responding. Last check: 2007-10-15)
		When the standard thermometer and the thermometer to be calibrated have reached equilibrium with the bath at a definite temperature, the point on the glass of the thermometer opposite the top of the mercury meniscus is marked.
		Let us insert one resistance thermometer bulb inside the pipe line and connect this bulb to the measuring bridge by means of two copper wires (b) and (c), which are routed through different plant locations, at different temperatures, before reaching the control room.
		The lead resistance changes due to ambient temperature variation is not compensated in thermocouple installation, where as this is fully compensated in the resistance bridge method of measurement.
	members.tripod.com /~Instengram/temp1.html (8092 words)

	resistance thermometer - Search Results - MSN Encarta
		Resistance (electricity), property of any object or substance to resist or oppose the flow of an electrical current.
		Resistance Movements, groups engaged in a struggle against military or totalitarian occupation or against other forms of social and political...
		- thermometer measuring temperature using electrical resistance: a thermometer that measures temperature by determining the electrical resistance of a wire coil or semiconductor placed where the temperature is to be measured
	encarta.msn.com /resistance+thermometer.html (152 words)

	Resistance thermometer - Wikipedia, the free encyclopedia
		Resistance thermometers, also called resistance temperature detectors (RTDs), are temperature sensors that exploit the predictable change in electrical resistance of some materials with changing temperature.
		Resistance thermometers are constructed in a number of forms and offer greater stability, accuracy and repeatability in some cases than thermocouples.
		Resistance thermocouples are usually made using platinum, because of its linear resistance-temperature relationship and its chemical inertness.
	en.wikipedia.org /wiki/Resistance_thermometer (1119 words)

	Eurotherm \| Knowledge \| Platinum Resistance Thermometer (Site not responding. Last check: 2007-10-15)
		The resistance of a conductor varies according to its temperature and this principle is employed in resistance thermometry.
		Since platinum is chosen for the world standard resistance thermometer material, the PRT assembly is the predominant choice for both laboratory and industry.
		During construction, the element resistance at 0°C is trimmed to 100 ohm to a very tight tolerance.
	www.eurotherm.co.uk /uk/eng/Knowledge/Sensors/PRT.htm (305 words)

	Super Thermometer Theory of Operation
		The 1575 makes precision resistance ratio measurements to determine temperature with an uncertainty of ±0.002°C or less, and the 1590 has an uncertainty of 0.00025°C. This technical note explains the instruments’ measurement technique, the functions of each circuit block and the sources of error and their solutions.
		The CPU then calculates the resistance of the sensor by multiplying the measured resistance ratio by the known resistance of the reference resistor.
		Consider nonlinearity to be curvature in the graph of the relationship between the actual resistance ratio and the resistance ratio measured by the 1575/1590.
	www.hartscientific.com /publications/super-theory.htm (2208 words)

	Resistance thermometer (Site not responding. Last check: 2007-10-15)
		'''Resistance thermometers''' are a type of temperature sensor and are slowly replacing the use of thermocouples in many lower temperature industrial applications (below 600°C).
		Resistance thermometers come in a number of construction forms and offer greater stability, accuracy and repeatability in some cases than thermocouples.
		Resistance thermocouples are usually made using Platinum, due to its stability with temperature.
	resistance-thermometer.iqnaut.net (793 words)

	other
		Basically a resistance thermometers is an instrument for measuring electrical resistance that is calibrated in units of temperature instead of in units of resistance.
		The thermometer bulb is immersed in the service medium to be measured and the increase in mercury volume due to temperature causes an increase of pressure which is measured by bourdon tube.
		Almost all pure metals have the property that their resistance changes with temperature and the change of resistance is directly proportional to the change of temperature.
	www.indiaboiler.com /steam10.htm (2841 words)

	Tinsley High Precision Platinum Resistance Thermometer Type 5187SA (Site not responding. Last check: 2007-10-15)
		This four terminal Precision Platinum Resistance Thermometer is designed to realise, with the highest accuracy, the International Temperature Scale ITS-90 over the range -189°C to 66O°C. The design is the result of many years practical experience and cooperation with the National Physical Laboratory, Teddington, where primary resistance and other standards are maintained.
		All the joints are welded, the four leads from the element to the seal in the thermometer head are heavier gauge platinum thereby avoiding the generation of thermal e.m.f.'s at the junction with the element.
		The thermometer is calibrated without the sheath and when this is in position the response time is increased to about 20 seconds.
	www.tinsley.co.uk /5187SA.htm (452 words)

	About Resistance Temperature Detectors, RTDs, PRTs, PRT100. SPRTs and Copper, Nickel and Other
		Resistance Temperature Detectors or RTDs for short, are wire wound and thin film devices that measure temperature because of the physical principle of the positive temperature coefficient of electrical resistance of metals.
		Transmitters convert the resistance measurement to an analog current or serial digital signal that can be sent long distances by wire or rf to a data aquisition or control system and/or indicator.
		Insulation resistance is always a function of temperature and at relatively high temperature the shunt resistance of the insulator introduces errors into measurement.
	www.temperatures.com /rtds.html (1222 words)

	Cryogenic Sensors - Germanium Resistance Thermometers (Site not responding. Last check: 2007-10-15)
		Resistance Thermometry is the accepted NBS standard for precision temperature measurement.
		Germanium also yields repeatability (the ability to produce the same resistance at a specified temperature after many thermal cycles), as opposed to many materials that tend to "age", or change characteristics, when repeatedly subjected to cryogenic temperatures; thus requiring constant calibration.
		The National Institute of Standards and Technology maintains germanium resistance thermometers as Primary Standards over the range of 2 degrees K to 20 degrees K. These thermometers are calibrated against the ITS 90, based on measurements with an acoustical thermometer.
	www.scientificinstruments.com /sensors/grt.htm (596 words)

	Chapter 14.2
		The electrical resistance of metals is strongly temperature dependent (the resistance increases with increasing temperature).
		The resistance of a platinum thermometer is low (10-100 ohms) and the temperature coefficient is also low (0.385 ohms/°C at 0°C) so the resistance measuring equipment must be sensitive and accurate.
		Thermistors are semi-conductors with a negative temperature coefficient (resistance decreases with increasing temperature).
	www.ucalgary.ca /~kmuldrew/cryo_course/cryo_chap14_2.html (982 words)

	Resistance Thermometers (RTDs) :: Peak Sensors
		Resistance thermometers come in a number of construction forms and offer greater stability, accuracy and repeatability.
		Commercial platinum grades are produced which exhibit a change of resistance of 0.385 Ohms/°C (European Fundamental Interval) The sensor is usually made to have 100 Ohms at 0 °C. This is defined in BS EN 60751:1996.
		Lead wire resistance should be considered and adopting three and four wire connection strategies can result in eliminating connection lead resistance effects from measurements.
	www.peaksensors.co.uk /rtddatasheets.html (731 words)

	RTD Measurement and Theory
		In fact, the Platinum Resistance Temperature Detector, or PRTD, is used today as an interpolation standard from the oxygen point (-182.96°C) to the antimony point (630.74°C).
		Its low resistivity forces the element to be longer than a platinum element, but its linearity and very low cost make it an economical alternative.
		The bridge output voltage is an indirect indication of the RTD resistance.
	www.omega.com /temperature/Z/TheRTD.html (1423 words)

	Isotech Standard Platinum Resistance Thermometers (SPRTS) (Site not responding. Last check: 2007-10-15)
		This is the first new thermometer, after the introduction of ITS-90, to be specifically designed to give optimum performance up to the aluminium point.
		Because the 670 goes beyond the temperature range of oxide growth to the level at which the oxide dissociates, the 670 is filled conventionally with argon containing 10% oxygen.
		A 2-metre length of low thermal emf, high temperature, screened cable is connected in the handle, via a strain-relieving transition, to the all pure-platinum construction of the thermometer.
	www.isotechna.com /Product.aspx?ProductID=547 (353 words)

	ME 117/220 Lecture #8
		For a voltage divider with a thermistor of average resistance R1 and a load resistor with resistance RL, the voltage at the output is given by
		The definition of the temperature coefficient as a fractional change in resistance per unit change in temperature produces a result in which the fractional change in voltage per unit change in temperature is given by alpha as well.
		Consider a general situation in which a thermometer is attached to an object with a thermal conductance of G (W/K).
	www.yale.edu /eas996/smart/lect_8.html (2181 words)

	Resistance Thermometer Calibration Curves
		Measure the resistance of your thermistor at various known temperatures, or obtain some calibration points from the manufacturer (such as the examples in the file thermis.txt).
		The first value in each measurement line is the temperature, the second value is the electrical resistance.
		With that definition the computed value of R is the ratio of the resistance at temperature T to the resistance at 25 degrees.
	www.moshier.net /rtd-readme.html (669 words)

	Platinum Resistance Thermometers for all instruments
		This is the 100 ohm platinum resistance thermometer with ceramic insulated leads and electrical connectors for the Finnigan MAT TSQ70®.
		This 100 ohm platinum resistance thermometer for the Incos 50 mass spec includes ceramic insulated leads as shown.
		This 100 ohm platinum resistance thermometer, for the Incos 50B mass spec has ceramic insulated leads and push on connectors.
	www.sisweb.com /ms/sis/prt.htm (609 words)

	NIST H143: Technical Criteria for Thermometer Laboratories
		This section may also be used as a guide by thermometer calibration laboratories in the development and implementation of their quality systems.
		When the reference standard used by the laboratory is a standard platinum resistance thermometer (SPRT) or a rhodium-iron resistance thermometer (RIRT), the two action items described below are recommended as indicated by the application table that follows them.
		When the reference standard used by the laboratory is a thermistor thermometer, the two action items described below are recommended as indicated by the application table that follows them.
	ts.nist.gov /WeightsAndMeasures/Publications/techcritthermo.cfm (1397 words)

	PMT-2005 PRECISION METEOROLOGICAL THERMOMETER
		The system consists of an aspirated triple-shielded platinum resistance thermometer and it represents the state-of-the-art in ambient temperature monitoring.
		The thermometer radiation shields are manufactured of aluminum with an electrostatically-applied white powder coating for long life.
		PMT-2005's 100 Ohm platinum resistance thermometer element is calibrated after packaging in a NIST-traceable temperature bath (Hart Scientific Model 7025 high precision bath).
	www.yesinc.com /products/data/pmt2005 (918 words)

	ATB-1250
		It allows the user to enter thermometer constants either manually or automatically and then read temperature (C or K) and resistance directly from the display.
		Conversion of resistance to temperature is accomplished by the standard IPTS-68 equation.
		The microprocessor performs the calculation of resistance to temperature while the bridge is digitizing.
	www.generaloceanics.com /genocean/atb1250.htm (485 words)

	Germanium Resistance Thermometer- Developer Zone - National Instruments
		A germanium resistance thermometer is used primarily for the cryogenic range of temperatures.
		The resistance measured between the leads is a nonlinear function of temperature.
		Two-lead germanium thermometer (a) and four-lead germanium thermometer (b).
	zone.ni.com /devzone/cda/ph/p/id/101 (237 words)

	Chart Recorders, Portable, Resistance Thermometer Inputs - Europe (Site not responding. Last check: 2007-10-15)
		In addition to digital thermometers, ETI Ltd manufactures a range of associated measuring instruments, which include Digital Hygrometers, Digital pH meters, and Moisture Meters.
		A full range of accessories is available, including anti bacterial probe wipes, plus a range of low cost traditional room thermometers and catering thermometers including the ever-popular Thermapen thermometer, which is suitable for both food-processing and for the professional chef.
		Supplying all your thermometer needs.Whether from our extensive stock or a one off manufactured special item, we can supply it to you.Please see our website for further info.
	www.kellysearch.com /qu-product-16645.html (647 words)

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