What is the meaning of temperature coefficient (TC) of resistance (ppm/C)?
It is a rate of change of the resistance value expressed in units of parts per million (ppm) when the temperature increases by 1C to a reference temperature. It is generally used as a gauge to show the temperature stability of a resistive element (i.e.: cermet is inherently more stable than carbon elements). It is expressed by the following formula: Temperature coefficient of resistance (TC) = (R2-R1) / (R1*(t2-t1)) X 106 (ppm/C) Where: t1 : Reference temperature expressed by C. t2 : Test temperature expressed by C. R1 : Resistance value at the reference temperature expressed in ohms. R2 : Resistance value at the test temperature expressed in ohms.