A thermistor is a
temperature dependent
resistor. This
means a
resistor that changes
resistance depending on its
temperature. There are two
types of thermistors, NTC and PTC.
NTC(
Negative temperature coefficient)s
resistance becomes lower
the higher
temperature it has. This type is used as
temperature sensors
in
cheaper
digital thermometers and
electronic thermostats.
PTC(
Positive temperature coefficient)s have a rising
resistance
when the
temperature gets higher. This
component is among other things
used in
electric motors to
prevent overheating.