and functions as a donor. The temperature dependent resistance, with the characteristic
of a PTC resistance, can thus be effectively adjusted by neutron irradiated silicon and
used as the sensor material. The actual temperature measurement is based on the
principle of "spreading resistance" according to
represents the specific
resistance of the doped silicon in
. d is the diameter of themeasurement contact
on the surface of the sensor andmust be negligibly small in comparison to the thickness
Dof the sensor.
The disadvantage of the design shown in
is that the resistance of the
silicon-metal bridge of the sensor is dependent on the direction of the current. Two
sensor cells are therefore usually connected in series, in order to achieve symmetrical
resistance regardless of whichdirection the current is flowing
The typical temperature range for a KTY sensor is from -50°C to 150°C and is
determined by the doping concentration. The reference resistance of the sensor is
specified at either 25°C or 100°C.
A very wide variety of packages is used, ranging from TO-92 to SOT-23 to designs for
hows, as an example, the characteristics of a KTY 10-6 with a constant
measuring current of 1mAandKTY84-130with 2mAmeasuring current.