Calculation of Self-Heating Current for a Resistance Wire Temperature Sensor

In many control or instrumentation circuits, a resistance wire temperature sensor is often used to measure the environmental temperature. Because the sensor current itself can change the resistance of the sensor, it is essential that the current required in the sensing circuitry does not cause excessive heating of the sensing element. The power loss caused by any current in the resistance sensor will always produce some change in resistance; a specific value for self-heating current is meaningful only when related to a specified percent deviation from the zero current resistance.