ATS Sensor Cheat Sheet - Advanced Thermal Solutions, Inc.

Sensor Cheat Sheet: Sensors
www.qats.com | 781-769-2800 | ats-hq@qats.com
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 Cheat Sheet: Thermocouples
www.qats.com | 781-769-2800 | ats-hq@qats.com
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
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