Sensor Quick Reference: Sensors www.qats.com | 781-769-2800 | [email protected] Transducer or Probe Temperature Sensitive Parameter Contact Method Remarks Resistor Electrical resistance or voltage at constant current Direct contact Usually calibrated against a thermocouple Thermocouple Open Circuit Voltage Direct contact Useful as a "point sensor" Diode or Transistor Voltage, usually with constant forward bias current Direct contact Usually employed to measure an active device or IC temperature Line-of-site or optical contact Yields a temperature map or image. Not strictly quantitative unless sample emittance is known at all image points Infrared or Radiation Detector Voltage Direct contact (proximity) Fluorescent Detector Liquid Crystal Detector Voltage Approximate point detector; contact resistance a problem Color Yields a temperature map; semi-quantitative unless a detailed calibration is performed to quantify color vs. temperature relation Direct contact Copyright® Advanced Thermal Solutions, Inc. 2012 1 Sensor Quick Reference : Thermocouples www.qats.com | 781-769-2800 | [email protected] Thermocouple Type Material A Material B V Output (µV) Norm. error; lim.+/- °C B Platinum -30%, rhodium Platinum -6%, rhodium 1 0 E Nickel-chromium alloy A copper-nickel alloy 62 1.7 J Iron A different coppernickel alloy 51 2.2 Iron P leg subject to variations in Seebeck coefficients from impurities K Nickel-aluminum alloy (Alumel) Nickel-chromium alloy (Alumel) 40 2.2 Very popular for electronics cooling experiments R Platinum -13%, rhodium Platinum 7 5 Very stable S Platinum -10% rhodium Platinum 7 5 T Copper Copper-nickel alloy 40 1 Copyright® Advanced Thermal Solutions, Inc. 2012 Remarks Not useful below 50°C; best for very high temperature measurements Well-suited for low temperature measurements Copper leg could create a conduction path (fin) insurface temperature measurements 2