Understanding Dissipation Constant

The dissipation constant (D.C) is the exact amount of power needed to self-heat thermistors that are suspended (with two-inch leads) in still air that is 1 °C higher than its environment. The D.C of an NTC thermistor assembly can be defined as the ratio of power dissipated in thermistor to the resultant changes in the thermistor’s temperature. D.C is expressed in milliwatts. This constant will change with increasing temperatures.

Dissipation constants are determined by several factors, which include:

Considering the number of factors above, it is recommended that prototypes are first tested in real-world conditions. This test will allow us to determine the maximum allowability of the input current. It is vital that the current running through the thermistor be small enough to create negligible self-heating error inside the thermistor while at maximum measuring. This must be done while trying to keep the current large (to help maximize system sensitivity).

At Sensor Scientific, we can help you navigate the confusing world of dissipation constant. We can help you create thermistors based on your specific needs.