Contents
What is the relationship between temperature and the thermistor?
NTC temperature thermistors have a negative electrical resistance versus temperature (R/T) relationship. The relatively large negative response of an NTC thermistor means that even small changes in temperature can cause significant changes in their electrical resistance.
Why are NTC thermistors good for temperature measurement?
The relatively large negative response of an NTC thermistor means that even small changes in temperature can cause significant changes in their electrical resistance. This makes them ideal for accurate temperature measurement and control.
Is the thermistor a linear or non linear sensor?
However, alternative forms of heavily doped thermistors are now available (at high cost) that have a positive temperature co-efficient. The expression (1) is such that it is not possible to make a linear approximation to the curve over even a small temperature range, and hence the thermistors is very definitely a non-linear sensor.
How are thermistors used in medical devices?
Engineers may use epoxy-protected thermistors to protect thermal conductivity and high dielectric strength. These thermistors are tear-drop-shaped bead that has two radial wire leads. These thermistors are used in medical devices that measure air temperature and airflow.
How are NTC thermistors used in temperature sensing?
If we reversed the positions of the series resistor, R S and the thermistor, R TH, then the output voltage would change in the opposite direction, that is the hotter the thermistor gets, the higher the output voltage. We can use NTC thermistors as part of a basic temperature sensing configuration using a bridge circuit as shown.
How is a thermistor used in a potential divider circuit?
As a thermistor is an passive type of a sensor, that is, it requires an excitation signal for its operation, any changes in its resistance as a result of changes in temperature can be converted into a voltage change. The simplest way of doing this is to use the thermistor as part of a potential divider circuit as shown.