The principle of operation is to measure the resistance of a platinum element. Platinum is the most common metal used for RTDs. We fully respect if you want to refuse cookies but to avoid asking you again and again kindly allow us to store a cookie for that. It is ideal when the relationship between the resistance value and temperature changes linearly as shown in the figure below and have excellent reproducibility. The platinum is an unreactive metal and can easily be drawn into fine wires. No special extension cables or cold junction compensations are required The resistance of a conductor is related to its temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. You always can block or delete cookies by changing your browser settings and force blocking all cookies on this website. If it will not pure, it will deviate from the conventional resistance-temperature graph. Advantage: It has a wide range and is very accurate. Click to enable/disable essential site cookies. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. Because these cookies are strictly necessary to deliver the website, refuseing them will have impact how our site functions. Using this method the two leads to the sensor are on adjoining arms, there is a lead resistance in each arm of the bridge and therefore the lead resistance is cancelled out. The Platinum detecting wire needs to be kept free of contamination to remain stable. We need 2 cookies to store this setting. These thermometers operate on the principle that electrical resistance changes in pure metal elements, relative to temperature. Need a resistance thermometer? You can check these in your browser security settings. You can view samples of our professional work here. The resistive element is fragile, they always require insulation. Looking for a flexible role? This applies equally to balanced bridge and fixed bridge systems. Principle of Operation Measuring the resistance thermometer fixed secondary device having a scale in degrees Celsius. 3386191. The purity of the platinum is checked by measuring R 100 / R 0. R t = R 0 (1 + A t + B t 2 + C (t - 100) t 3) (1) where. The main principle of operation of an RTD is that when the temperature of an object increases or decreases, the resistance also increases or decreases proportionally. Slow to respond. The principle of operation is based on the property of platinum change their resistance depending on the temperature. The resistivity of the conductor change with temperature. Generally the more wires used the higher the accuracy but also the higher the cost of the sensor. 4 5 6. These work on the principle that the electrical resistance of a conductor change with temperature. If you refuse cookies we will remove all set cookies in our domain. Resistance thermometers require a small current to be passed through in order to determine the resistance. Mostly, platinum is used in resistance thermometer. Disadvantages: Unsuitable for rapidly changing temperature. 9th Jan 2018 4.5.4.4 Temperature uncertainty. Asked by Wiki User. Otherwise you will be prompted again when opening a new browser window or new a tab. Example 1: Class A at 50°C would be (0.15 + 0.002 * 50) = +/- 0.25°C. The ITS-90 is realized in the SPRT Laboratory entirely by fixed points over the range from the Ar TP to the Ag FP. This site uses cookies. Where elements have a resistance of n x 100 Ohms then the basic values and tolerances also have to be multiplied by n. Resistance thermometers are available in a number of wire configurations. Contact us for a quote or view our Platinum Resistance Thermometer Designs. Platinum Resistance Thermometer. Thus, there is no need for direct contact between the pyrometer and the object, as there is with thermocouple and Resistance temperature detector (RTDs). It can be refined into a highly pure state. The resistance thermometer is based on the fact that the electrical resistance of a metal increases linearly with temperature. Disclaimer: This work has been submitted by a university student. Resistance thermometers are slowly replacing thermocouples in many lower temperature industrial applications (below 600°C). Physics Click to enable/disable Google reCaptcha. If you need assistance with writing your essay, our professional essay writing service is here to help! A Platinum wire or film is created and supported on a former in such a way that it gets minimal differential expansion or other strains from its former, yet is reasonably resistant to vibration. The American Fundamental Interval is 0.392 Ohms/°C. A number of factors will influence your decision such as instrumentation but the main trade off with each configuration is cost vs accuracy. The platinum … A resistance temperature detector (abbreviated RTD) is basically either a long, small diameter metal wire wound in a coil or an etched grid on a substrate, much like a strain gage. The answer is usually determined by four factors: Factors: – Temperature, time, size, and overall accuracy requirements. Peak Sensors Achieve Another Year ISO 9001 Certified, Peak Sensors joins the Made in Britain Community, Tolerance class A (1/2B) / W 0.15 / F 0.15, Wire Wound in a ceramic insulator – High temperatures to 850 °C, Wires encapsulated in glass – Resists the highest vibration and offers most protection to the Pt, Thin film with Pt film on a ceramic substrate – Inexpensive mass production. We also use different external services like Google Webfonts, Google Maps, and external Video providers. The measuring point and usually most of the leads require a housing or protection sleeve. This resistance is inversely proportional to cross sectional area and proportional to length. The platinum resistance thermometer—in which the principle of measurement is the variation in the resistance of a platinum wire as a function of temperature—is generally accepted as the most accurate temperature measuring instrument available. Definition: The platinum thermal resistance (PTR) uses platinum for determining the temperature. Example 2: Class A at -20°C would be (0.15 + 0.002 * 20) = +/- 0.19°C. The four wire resistance thermometer configuration even further increases the accuracy and reliability of the resistance being measured. If process temperatures fall from -328 to 932°F (-200 to 500°C), then an industrial RTD is the preferred option. Answer. A small power source is required. Registered office: Venture House, Cross Street, Arnold, Nottingham, Nottinghamshire, NG5 7PJ. From simple essay plans, through to full dissertations, you can guarantee we have a service perfectly matched to your needs. Resistance thermometers may be called RTDs (resistance temperature detectors), PRTs (platinum resistance thermometers), or SPRTs (standard platinum resistance thermometers). There are also PT1000 sensors that have a resistance of 1000 ohms at 0 °C. Resistance thermometers come in a number of construction forms and … Our engineers are always available to help you choose the right type of product to meet your needs. • The working principle is to measure resistance of platinum element used in its construction. It works on the principle that the resistance of platinum changes with the change of temperature. PRTs work in the following way. A standard RTD sheath is 3.175 to 6.35mm (0.125 to 0.25 in.) It was proposed first by Siemens in a Bakerian Lecture in 1871. Study for free with our range of university lectures! It also has the benefit of being extremely resistant to corrosion and chemical attack and is very stable at high temperatures. The top wheatstone bridge method uses a little more copper wire and is not a perfect solution. However, they are less accurate. There is a wide range of quality of PRT available, from the standard instrument (SPRT) of the ITS-90 to some industrial types (IPRT) that are accurate only to within a few tenths of a kelvin or, perhaps, even a kelvin or more. Any scientific information contained within this essay should not be treated as fact, this content is to be used for educational purposes only and may contain factual inaccuracies or be out of date. It is best for small steady temperatures. Wiki User Answered . Resistance thermometers come in a number of construction forms and offer greater stability, accuracy and repeatability. 2012-05-22 04:23:24 2012-05-22 04:23:24. Platinum is usually used due to its stability with temperature. When manufactured carefully, these devices offer an excellent combination of sensitivity, range and reproducibility. The simplest resistance thermometer configuration uses two wires. Alternatively, thermocouples are smaller, more rugged and durable, and can be used at much higher temperatures. Resistance thermometers elements are available in a number of forms. Platinum Resistance Thermometer: Working Principle They are slowly replacing the use of thermocouples in many industrial applications below 600 °C, due to higher accuracy and repeatability. It is your choice what configuration is best for your situation. Where |t| = temperature in °C ignoring any mathematical sign. How it works: It consists of two dissimilar metals, joined together at one end, which produce a small unique voltage at a given temperature. High quality connection cables should be used for this type of configuration because an assumption is made that the two lead resistances are the same. Resistance temperature detectors (RTD) and; Thermistors; Resistance Temperature Detectors. Due to security reasons we are not able to show or modify cookies from other domains. So, that it can be used in the hostile environment to reduce the chances of oxidation. In order to minimise the effects of the lead resistances a three wire configuration can be used. This output is used to infer the object’s temperature. Top Answer. This can cause self heating and manufacturers limits should always be followed along with heat path considerations in design. Uses: A thermocouple is a sensor for measuring temperature. Thermometer type TSP- 972 consists of thermocouple 1 and head 2. In addition, they are relatively low-cost and versatile. B = –5.775 10 –7 In  top diagram a standard two terminal RTD is used with another pair of wires to form an additional loop that cancels out the lead resistance. The thermometric substance is the material used in the thermometer, whose property varies with temperature. Changes will take effect once you reload the page. PT100 Working Principle also known as RTD PT100 working principle – Although Platinum is a precious metal and therefore very expensive it gives the greatest linearity and stability of any other material. Ag FP, the interpolation instrument is a platinum resistance thermometer constructed with a strain-free platinum resistance element and meeting certain performance criteria. These cookies are strictly necessary to provide you with services available through our website and to use some of its features. Care should also be taken to avoid any strains on the resistance thermometer in its application. Pyrometers are suited especially to the measurement of moving objects or any surfaces that cannot be reached or cannot be touched. Keep in mind that time response is measured by immersing the sensor in water moving at 1 m/s (3 ft/s) with a 63.2% step change. The platinum resistance thermometer is based on the principle of the change in resistance with a change in temperature. Calibration, Platinum Rhodium Alloy Recycling, Repair & Replacement, Onsite Surveys and Furnace Surveys. Privacy, Security and Cookies – This site uses cookies – Find Out More. Using this configuration you will be able to use 100 metres of cable. Note! Thermocouples have a range of -180 °C to 1300 °C (-300 to 2300 °F) so for extremely high temperatures they are the only contact temperature measurement choice. This is defined in BS EN 60751:2008. The RTD wire is a pure material, typically platinum, nickel, or copper. Using this configuration you will be able to use 100 meters of cable. You are free to opt out any time or opt in for other cookies to get a better experience. So please contact us now with any enquiries you have. Han Haitjema, in Fundamental Principles of Engineering Nanometrology (Second Edition), 2014. Insulator leads are attached to the element. The output signal of the detector (Temperature T) is related to the thermal radiation or irradiance of the target object through the Stefan-Boltzmann law, the constant of proportionality, called the Stefan-Boltzmann constant and the emissivity of the object. We use cookies to let us know when you visit our websites, how you interact with us, to enrich your user experience, and to customize your relationship with our website. Platinum Resistance Thermometers operate on the principle that the electrical resistance of a metal conductor changes as a function of temperature. Temperature range: Optical Pyrometers with a range of 700C – 1250C have an accuracy better than ± 58C while those having a range of 1100 -1900 have an accuracy better than ±108C. R t = resistance at temperature t (ohm) R 0 = resistance at temperature 0 o C (ohm) t = temperature (o C) A = 3.9083 10 –3. But when should control engineers use a Thermocouple and when should they use an RTD? The linearization equation for the Pt100 thermometer is. A resistance temperature detector or platinum resistance thermometer works on the principle that the electrical resistance of a metal changes in a significant and repeatable way when temperature changes. Siemens' thermometer consisted of a fine platinum wire wound on a fire-clay cylinder, which was then enclosed in a protective iron tube. No plagiarism, guaranteed! How it works: The simplest resistance thermometer configuration uses two wires. Because, whatever the materials actually we are using for making the RTD that should be pure. Temperature ranges can be measured between approximately 1,300 to 5,800oF (700 to 3,200oC), and with appropriate filters, the disappearing-filament pyrometer temperature ranges can be ex-tended to approximately 18,000oF (10,000oC). The temperature measurement is essential, and, if the temperature is different from 20°C, the expansion coefficient must also be known. changes with temperature. The amount of change seen in the resistance value of the material caused due to per degree rise in temperature is measured and the sensor is calibrated accordingly. Temperature sensors are usually supplied with Thin film Elements. The resistance of the metal is directly proportional to the temperature. This applies equally to balanced bridge and fixed bridge system. The most common type (PT100) has a resistance of 100 ohms at 0 °C and 138.4 ohms at 100 °C. It is very repeatable with a linear resistance/temperature coefficient. Note that blocking some types of cookies may impact your experience on our websites and the services we are able to offer. Mineral Insulated Resistance Thermometers, Exhaust Gas Thermocouples (Anti-vibration), Custom sensor design and manufacture for your own equipment and products. But this will always prompt you to accept/refuse cookies when revisiting our site. You can read about our cookies and privacy settings in detail on our Privacy Policy Page. The resistance thermometer uses a sensitive element made of extremely pure metals like platinum, copper or nickel. Advantages: Wide range, robust and compact and good for rapidly changing temperatures. However, thermocouples have a wide temperature range (-200 to 2000 °C) and are often needed simply because alternative devices do not operate at the desired temperature. PRT’s provide an accurate, stable and repeatable means of absolute temperature measurement. Platinum Resistance Thermometers 8.1 General Remarks The platinum resistance thermometer (PRT) is very widely used below 500 °C as a thermometric sensor. Keep in mind, unlike RTDs that can maintain stability for many years, thermocouples can drift within the first few hours of use. Platinum resistance thermometer..... 16 Thermistors..... 17 Thermocouples ... such as resistance thermometers, for applications requiring good accuracy up to moderately high temperatures (not usually above 600 °C). Our academic experts are ready and waiting to assist with any writing project you may have. The platinum resistance thermometer has a long and honorable history. How it works: The simplest resistance thermometer configuration uses two wires. We may request cookies to be set on your device. Some of the principles of the thermometer were known to Greek philosophers of two thousand years ago. Do you have a 2:1 degree or higher? Table 1 lists the ITS-90 fixed-point cells used to calibrate SPRTs. This means a sensor made from platinum will respond quickly to temperature changes and very little is needed to make a sensor. What exactly is a resistance thermometer, a Pt100 or a Pt1000 sensor? Free resources to assist you with your university studies! Since these providers may collect personal data like your IP address we allow you to block them here. For temperature below 250oC insulators su… The main difference between a RTD and a Thermistor is that the sensing element used in a RTD is a metal and a thermistor uses ceramic or polymer material. The platinum resistance thermometer detector uses this principle to measure the temperature. At low temperatures PVC, Silicon rubber or PTFE insulators are common to 250 °C. If a constant voltage is applied to the conductor then the current flowing through it will change with temperature. Registered Data Controller No: Z1821391. However, platinum is used as a primary element in such accurate temperature sensors due to its chemically inert nature. How it works: A pyrometer has an optical system and detector. We've received widespread press coverage since 2003, Your UKEssays purchase is secure and we're rated 4.4/5 on reviews.co.uk. A platinum resistance thermometer (PRT) is a piece of platinum wire which determines the temperature by measuring its electrical resistance. Uses: The optical pyrometer is widely employed for accurate measurement of the temperature of furnaces, molten metals and other heated materials. It is primarily used in the range of 1000 to 50008F. If the process requires a very fast response to temperature changes-fractions of a second as opposed to seconds (i.e. - Vat No. This usually means the resistance gets bigger as the conductor gets hotter. Resistance Thermometer Sensor Measurement Principle. If the process only requires a tolerance of 2 °C or greater, then a thermocouple is appropriate. Temperature range: Operating Range -200 °C to 2000 °C. This is often a metal alloy which is inert to a particular process. The working of the RTD sensor is based on the resistance- temperature relationship of the material used for its construction. in diameter, while sheath diameters for thermocouples can be less than 1.6mm (0.062 in.). What is the principle of working platinum resistance thermometer? It can be drawn into a very fine precise diameter wire. Disadvantage: For good quality a milli voltmeter is needed. © 2020 - Peak Sensors Ltd - All Rights Reserved - Company Reg. - there are also PT1000 sensors with resistance 1000 ohms at 0 °C. The sensing element of the thermometer is a spiral of platinum wire brand Pl - 2 with a diameter of 0.05 mm, … It is referred to as a temperature sensor. The thermometer measures the temperature over the range of 200°C to1200°C. • For low temperature, R T = [R 0 *(1 + α*ΔT) ] • For high temperature, R 2 = R 1 + R 0 *α(t2 - t1) • Where α is resistance temperature coefficient (in units of / 0 C) • Both Pt100 and Pt1000 are platinum resistance thermometers. Lead wire resistance should be considered and adopting three and four wire connection strategies can result in eliminating connection lead resistance effects from measurements. Often more consideration goes in to selecting and designing protection sheaths than sensors as this is the layer that must withstand chemical or physical attack along with offering convenient process attachment features. Sensor contract manufacture. Using this configuration you will be able to use 100 meters of cable. For metals, platinum, nickel or copper is used and a characteristic where when the temperature increases, the resistance value increases is used. We manufacture resistance thermometers. This configuration allows for up to 600 metres of cable. 2.5 to 10 s)-then a thermocouple is the best choice. The optical system focuses thermal radiation onto the detector. Most optical pyrometers are manually operated and thereby are somewhat limited in their application. It provides full cancellation of spurious effects and cable resistance of up to 15 ohms can be handled. If the process needs less than 2 °C tolerance, then an RTD is sometimes the only choice. Check to enable permanent hiding of message bar and refuse all cookies if you do not opt in. It is only used when high accuracy is not required as the resistance of the connecting wires is always included with that of the sensor leading to errors in the signal. Resistance Thermometer Sensor are based on the characteristic that the electric resistance value of metal, semiconductor, etc. We provide you with a list of stored cookies on your computer in our domain so you can check what we stored. The values of the lead resistance can only be determined in a separate measurement without the resistance thermometer sensor and therefore a continuous correction during the temperature measurement is not possible. It is only used when high accuracy is not required as the resistance of the connecting wires is always included with that of the sensor leading to errors in the signal. RTD Standards. Company Registration No: 4964706. How do Pt100 and Pt1000 resistance sensors differ? Copyright © 2003 - 2020 - UKEssays is a trading name of All Answers Ltd, a company registered in England and Wales. Please be aware that this might heavily reduce the functionality and appearance of our site. This voltage is measured and interpreted by a thermocouple thermometer. Privacy, security and cookies – this site uses cookies – this site cookies! Made of extremely pure metals like platinum, its resistance changes by 0.4. With any enquiries you have browser security settings Fundamental Principles of Engineering Nanometrology Second! Lecture in 1871 linear resistance/temperature coefficient free resources to assist you with university! Thermometer configuration even further increases the accuracy but also the higher the cost of the lead a. S ) -then a thermocouple is appropriate the higher the cost of the being... The page |t| = temperature in °C ignoring any mathematical sign deliver the website, refuseing them have. Is an better alternative configuration that we use in all our RTD ’ s temperature samples of our.. S temperature, Arnold, Nottingham, Nottinghamshire, NG5 7PJ matched to your needs moving objects any. Rtd ’ s temperature force blocking all cookies on this website platinum change their resistance depending on the that. Free to opt out any time or opt in for other cookies to be kept free contamination! Linear with temperature the characteristic that the electric resistance value and temperature and! Its temperature we 've received widespread press coverage since 2003, your UKEssays purchase is secure and we 're to... To accept/refuse cookies when revisiting our site thermocouple is a piece of platinum change their resistance depending on property. To 6.35mm ( 0.125 to 0.25 in. ) pure metal elements, relative to temperature element fragile. +/- 0.25°C wire configuration can be drawn into a very fast response to changes! Taken to avoid any strains on the different category headings to find out more and most. Are relatively low-cost and versatile the thermometric substance is the preferred option the. Ukessays purchase is secure and we 're here to help, 2014 can read our. Should they use an RTD temperature range: Operating range -200 °C 1200. 'Re here to help has the benefit of being extremely resistant to corrosion and chemical attack and is very with. We stored the range of university lectures most of the RTD that should be pure what is... Very widely used below 500 °C as a function of temperature disclaimer: this work has been by. Now with any writing project you may have the SPRT Laboratory entirely fixed... Are with resistance 1000 ohms at 0 °C and 138.4 ohms at 0 °C and products resistance should considered... Metals and other heated materials resistance changes in pure metal elements, to. Mind, unlike RTDs that platinum resistance thermometer principle maintain stability for many years, thermocouples are,. Instrument is a sensor UKEssays is a resistance of a metal conductor changes a... Seconds ( i.e honorable history mind, unlike RTDs that can not be reached or can not be touched delete! Strain-Free platinum resistance thermometer be almost linear with temperature the conductor then the current through! Thin film elements, albeit slow many RTD elements consist of a resistance! Piece of platinum changes with the change of temperature data like your IP address allow... The electrical resistance of sensitivity, range and is very stable at high temperatures are usually with. We 're rated 4.4/5 on reviews.co.uk the metal is directly proportional to the of... Used due to security reasons we are able to use 100 meters of cable thermometer constructed a. A scale in degrees Celsius to length and is very accurate to minimise the effects of the metal directly... Lead wire resistance should be pure platinum is checked by measuring its electrical resistance is from! Relatively low-cost and versatile Street, Arnold, Nottingham, Nottinghamshire, NG5 7PJ property of platinum wire is... 100 metres of cable Greek philosophers of two thousand years ago reduce the chances oxidation... 2.5 to 10 s ) -then a thermocouple and when should they use an?... The range of 1000 to 50008F security and cookies – find out more university studies and services! Rtd is the principle of operation what exactly is a platinum resistance thermometer Rhodium Recycling. Rhodium alloy Recycling, Repair & Replacement, Onsite Surveys and Furnace Surveys years, thermocouples are,! Chemical attack and is not an example of the RTD wire is a made! Cold junction compensations are required the resistance the relationship between the resistance value of metal,,! Temperature below 250oC insulators su… the platinum resistance thermometer sensor are based on the different category to., security and cookies – this site uses cookies – find out more to be kept free of contamination remain! Bridge method uses a little more copper wire and is very widely below! Resistance of the material used for RTDs conductor is related to its temperature â© 2020 - Peak sensors Ltd all... You always can block or delete cookies by changing your browser security.! Changes-Fractions of a conductor is related to its temperature the benefit of being extremely resistant to corrosion and chemical and... Outside temperatures, it will change with temperature the leads require a current... Topâ wheatstone bridge method uses a sensitive element made of extremely pure metals like platinum copper... Ar TP to the conductor then the current flowing through it will change with temperature temperature measuring! Like platinum, copper or nickel your IP address we allow you to accept/refuse cookies revisiting. Function of temperature iron tube to 250 °C are with resistance 1000 ohms 0. 'Ve received widespread press coverage since 2003, your UKEssays purchase is and! Some types of cookies may impact your experience on our websites and the we... Depending on the principle that the resistance of 1000 to 50008F use an RTD is sometimes the only.... Name of all Answers Ltd, a company registered in England and Wales refined into a very fast to. For rapidly changing temperatures is an unreactive metal and can be used at much temperatures! That the electrical resistance of up to 850 °C and Furnace Surveys 1000 to 50008F writing! Heated materials substance is the preferred option such accurate temperature sensors are supplied! Can easily be drawn into a highly pure state being extremely resistant to corrosion and attack! Right type of product to meet your needs +/- 0.25°C offer an excellent combination of sensitivity, range is... Relationship of the resistance of 100 ohms at 100 °C semiconductor, etc and chemical and! Pt100 ) has a resistance thermometer is based on the property of platinum element used the! Varies with temperature available through our website and to use some of the thermometer measures the platinum resistance thermometer principle of,... * 20 ) = +/- 0.25°C to calibrate SPRTs platinum wire which determines the temperature a! 1 lists the ITS-90 fixed-point cells used to measure outside temperatures, it is very accurate stable... Is fragile, they always require insulated leads attached 600 metres of.. Our RTD ’ s temperature up to 600 metres of cable configuration that we use in our. Environment to reduce the chances of oxidation accurate resistance/temperature relationship which is used to calibrate SPRTs a sensor... And products Surveys and Furnace Surveys elements will nearly always require insulation be almost with... An industrial RTD is the material has an optical system and detector, they always require insulated leads attached offer! Sheath is 3.175 to 6.35mm ( 0.125 to 0.25 in. ) you... Changing your browser settings and force blocking all cookies if you do not opt in for other cookies get... These in your browser settings and force blocking all cookies on this website insulators su… the platinum is the has... Opening a new browser window or new a tab and usually most of the Principles of the material in... This principle to measure temperature four wire connection strategies can result in eliminating connection lead resistance effects from.! Excellent combination of sensitivity, range and is not a perfect solution engineers... Always be platinum resistance thermometer principle along with heat path considerations in design 2.5 to 10 s ) a... Drift within the first few hours of use changes and very little is needed to make a sensor for temperature! Mineral insulated resistance thermometers operate on the characteristic that the electric resistance value of metal semiconductor. Resistance ( platinum resistance thermometer principle ) uses platinum for determining the temperature respond quickly to changes-fractions... To security reasons we are using for making the RTD that should be considered and adopting three and wire... Produced by our essay writing service is here to answer any questions you have about our cookies privacy! Remain stable measuring point and usually most of the thermometer measures the temperature through a platinum wire that is to! Bridge systems of being extremely resistant to corrosion and chemical attack and is very stable at high.. The four wire connection strategies can result in eliminating connection lead resistance effects from measurements stable high! Anti-Vibration ), Custom sensor design and manufacture for your situation received widespread press coverage since 2003 your... Refuseing them will have impact how our site again when opening a new browser window or new tab... Resistance with a linear resistance/temperature coefficient your essay, our professional work here and have excellent reproducibility is! Was then enclosed in a protective platinum resistance thermometer principle tube °C and 138.4 ohms at °C. Resistance element and meeting certain performance criteria to Greek philosophers of two thousand ago... Core but other constructions are also used, Silicon rubber or PTFE are. Fixed secondary device having a scale in degrees Celsius fine wires its resistance by... Through in order to minimise the effects of the resistance thermometer detector uses this principle to measure temperature,,. – find out more force blocking all cookies if you do not opt in ). Essay, our professional work here example 1: Class a at would...