Effect of Temperature on the Resistivity of a Semiconductor

Effect of Temperature on the Resistivity of a SemiconductorIntroductionA thermal resistor is a voltaic resistance thermometer, or a resistor whose resistance is dependent on temperature. The term is a combination of thermal and resistor. It is do of metallic oxides, pressed into a bead, disk, or cylindrical shape and consequently compressed with an impermeable satisfying such as epoxy or glass. This means that they argon made out of semiconductor device material, which shows changes in resistance depending on changes in temperature. Due to their predic dishearten characteristics and long-term stabilityit stub be flierd by using a small and measured direct current or dc passed through the thermistor in frame to measure the voltage drop produced. Thermistors are an implausibly accurate category of temperature sensors.In this experiment we expect that as temperature decreases as the resistivity increasesTheoryIn this experiment we are to prove direct evidence for the effect of the temperature on the resistivity of a semiconductor thus, the thermistor. Some devices made of semiconductors decrease their resistance as the temperature increases due to the extra energy, which makes the atoms release electrons, permitting them to move more easily, this in turn reduce the resistance. T is for temperature and the unit is Kelvin (K). R is for resistance the unit is Ohms ().Resistance thermometry is a temperature measurement technique that uses the change in electrical resistance of a material as its temperature changes.They are two types of thermistors. The less used is theresistance temperature detectors (RTD .The most suitable type of thermistor used is the prejudicial temperature coefficient (NTC) thermistor, which consists of two terminal solid-state electronic mechanisms that displays a huge, expected difference in resistance twin(a) to changes in the absolute body temperature. A simple estimate for the bond between resistance and temperature for a NTC th ermistor is the use of the exponential approximation between both. It is based on the easy curve registration to the experimental data and uses two points on the curve to determine the value of the value of . The equation relating resistance to temperature using isWhereR = thermistor resistance at temperature TA = constant of equation = beta, the material constantT = thermistor temperature (k)Health and safetyHealth and safety instructions are principally common sense precautions but one has to be careful. In addition, flyers are printed out pasted on notice boards, windows and doors make it clearer and obvious not one to miss the principal instructions of each experiment. Instructors are there to constantly remind and read out instructions of the laboratory use and to report and perchance solve any predicted damage. In this experiment we take these precautionsEnsure that lab coats are worn settle sure that the beaker is held from the top rather than the bottom to avert unpropit ious effects of the heat at the bottom. tag on the digital mul cartridge holderter on and off where necessaryEnsure beaker has no linkagesAvoid parallax error on the thermometer and beaker by observing it at eyelevel.Assure lab equipments are kept well on the table to debar falling down on to feet i.e. hot water on feetApparatus UsedIn order to do this experiment we require to posses these apparatus2 x 4 mm connecting leads, one digital multimeter set on resistance range, Source of sultry dihydrogen monoxide an electric kettle, Frozen dihydrogen monoxide cubes or Crushed frosty dihydrogen monoxide, A Thermistor 1 thermometer, Stirrer,1 x 500 ml beakerTechniqueI put dihydrogen monoxide in an electric kettle for it to boil while I placed thermistor wrapped with a thermometer in the beaker, utilized the leads and crocodile clips designated for the purport of the annexation of the cables. I now situated the beaker at the base of the retort stand, structured turn dihydrogen monoxide received from the electric kettle in to it to a 300 ml mark. I indeed ascertained that the retort is opportunely in position such that the thermometer does not all to deep into the boiling dihydrogen monoxide. I adjusted the multimeter to a range of 20K as verbalized in the instructions and poured in few cold dihydrogen monoxide / crushed frozen dihydrogen monoxide. I now accumulated and record the data of the immersion weed in a table and the temperature and resistance every 5C is recorded warm the dihydrogen monoxide. The electric kettle is then further used to increment temperature. Crushed frozen dihydrogen monoxide was put from time to time to avail expedite the rate at which the temperature decremented.ResultsFrom the experiment, for every 5c vicissitude in temperature the conclusion value of the resistance is quantified. From table below we revealed that two values for resistance were taken (R1 and R2) which are in ohms (). This was done to ascertain precision and precisi on in readings is preciseAdditionally, from the table it is observed that the logarithm of the fair(a) resistance is taken, it is represented as Ln(R) in the table. Additionally, it is descried from table 1 that as the temperature decremented the resistance incremented.1 it is in addition descried that as the temperature decremented the logarithm of the average resistance incremented.DiscussionFrom the first chart of average resistance against temperature it is pragmatic sanction that the graph gives a curve whereas the second graph, which is the graph of logarithm of the resistance against temperature, gives a linear graph.Likewise, from the graph it is observed that as the temperature decreases the resistance increases. This implicatively insinuates that the thermistor used is a negative temperature coefficient (NTC) thermistor. It is additionally observed from table that as the temperature decremented the value of the logarithm of the average resistance incremented. This migh t have been done to speed up the process therefore altering some of the values.In addition, the thermistors have advantages over thermocouple. They have a high signal to noise ratio compared with that of a thermocouple and due to their smaller size they respond speedy to temperature difference. However, thermistors are insubstantial are not easily changeable and are expensive times when favor is requiredConclusionThe values gotten shows the resistivity increases as the temperature decreases. It is believed that the calibration process presented here represents arock-steady technique by which to achieve the required temperature-measurement.One way to describe the curve of an NTC thermistor is to measure the slope of the resistance versus temperature (R/T) curve at one temperature. By definition, the coefficient of resistance is given by =1R * dR / dTReferencesAmetherm.com, (n.d.). What is an NTC Thermistor Ametherm. online Available at http//www.ametherm.com/thermistor/what-is-an -ntc-thermistor Accessed 29 Oct. 2014.Ametherm.com, (n.d.). Thermistor Temperature Sensing Ametherm. online Available at http//www.ametherm.com/thermistor/ Accessed 29 Oct. 2014.Analog Technologies, (n.d.). High Stability Miniature Thermistor. online Available at http//www.analogtechnologies.com/document/ATH10K1R25.pdf Accessed 29 Oct. 2014.Markedbyteachers.com, (n.d.). Resistance Ohms Law GCSE Science Marked by Teachers.com. online Available at http//www.markedbyteachers.com/gcse/science/resistance-ohm-s-law.html Accessed 29 Oct. 2014. measuring Specialties, Inc., (n.d.). online Available at http//precisionsensors.meas-spec.com/default.asp Accessed 29 Oct. 2014.Precisionsensors.meas-spec.com, (n.d.). Sensors Measurement Specialties, Inc. online Available at http//precisionsensors.meas-spec.com/default.asp Accessed 29 Oct. 2014.Teamwavelength.com, (n.d.). Thermistor Basics. online Available at http//www.teamwavelength.com/info/thermistors.php? Accessed 29 Oct. 2014.Sanusi Dang oteGroup S6PHYSICS LAB REPORT