How do the PASCO Temperature Sensors work?
10 kOhm NTC Thermistors
The following equipment measure the resistance of a 10 kOhm ceramic metal-oxide negative temperature coefficient thermistor that was designed to have resistance of 10.00 kOhm at a temperature of 25.00 C:
The thermistor is connected between the tip and sleeve (base) of the TRS connector. The ring is not connected. The equation for the temperature in terms of the resistance is given by the (Steinhart-Hart) equation below:
Temperature[Celsius] = 1.0 / ( A + B ln(R) + C ln(R)^2 + D ln(R)^3 ) - 273.15
100 kOhm NTC Thermistors
The following sensors use a version of the ceramic metal-oxide negative temperature coefficient thermistor that is designed to have a resistance of 100.0 kOhm at 25.00 C:
The equation for the temperature in terms of the resistance is given by the (Steinhart-Hart) equation below:
Temperature[Celsius] = 1.0 / ( A + B ln(R) + C ln(R)^3 ) - 273.15
Type K Thermocouples
Type K thermocouples are good for measuring a much wider temperature ranges than NTC thermistors, but are less accurate. Thermocouples consist of a junction between two conductors with different work functions. Thermocouples output a voltage that is nearly proportional to the difference in temperature between the two conductors, and their non-linearity is well compensated. As thermocouples can only measure differences in temperature, the temperature at the cold side of the junction is typically measured by a thermistor to calculate the actual temperature.
Creation Date: 09/18/2003
Last Modified: 06/5/2014