Research on measurement method of temperature sensor´s thermal time constant based on constant power injecting

Based on the cognition that the rate of thermal energy exchange between temperature sensor and the medium by which the sensor is surrounded is independent of the sensor´s static characteristic, a measurement method of thermal time constant of temperature sensor is put forward, it does not use the sensor´s static characteristic. The algebra equation of thermal time constant of temperature sensor is derived. On this method the identical sensor is heated by constant power twice in the identical medium. In the two processes, the two sensor temperature values in the beginning of heating and the two sensor temperature values in the ending of heating are identical respectively, and the two power values are not equal to each other. The thermal time constant of temperature sensor can be figure out according to the heating duration and the power values in the two processes. The method is rigorous in theory, is feasible in technology, and has no measurement errors coming from the discreteness and nonlinearity of the sensor´s static characteristic. It provides the theoretical basis and technical means for measuring thermal time constant of contact temperature sensor accurately.