Thermistors are thermally sensitive resistors whose prime
function is to exhibit a large, predictable and precise change
in electrical resistance when subjected to a corresponding
change in body temperature. Negative Temperature Coefficient
(NTC) thermistors exhibit a decrease in electrical resistance
when subjected to an increase in body temperature and Positive
Temperature Coefficient (PTC) thermistors exhibit an increase in
electrical resistance when subjected to an increase in body
temperature. U.S. Sensor produces thermistors capable of
operating over the temperature range of -100 ? to over +600 ?
Fahrenheit. Because of their very predictable characteristics
and their excellent long term stability, thermistors are
generally accepted to be the most advantageous sensor for many
applications including temperature measurement and control.
Since the negative temperature coefficient of silver sulphide
was first observed by Michael Faraday in 1833, there has been a
continual improvement in thermistor technology