Wednesday, December 15, 2010

Weak current College】 【thermistor technology parameter】.

<br> ① nominal resistance Rc: generally refers to the ambient temperature is 25 ° c, the actual resistance of the thermistor. <br> <br> ② the actual resistance RT: at certain temperatures the resistance value. <br> <br .> ③ material constants: it is a description of the physical characteristics of the thermistor material parameters, it is B thermal sensitivity index, the higher the value, the higher the sensitivity of the thermistor. It should be noted that, in practice, the B .value is not a constant, but rather with temperature rise slightly increased. <br> <br> ④ resistance temperature coefficient α T: it indicates the temperature resistance of 1 ° c, the rate of change units to% / ℃. <br> .<br> ⑤ time constant τ: thermistor is a thermal inertia, the time constant is a description of the thermistor heat inertia parameter. It is defined as, in the absence of power, when the ambient temperature by a specific temperature to another specific temperature .suddenly changed, thermistor temperature variation of two specific temperature difference of 63.2%. The smaller the τ indicates thermistor, the smaller thermal inertia. <br> <br> ⑥ rated power PM: the technical conditions, thermistor long-term continuous load allowed dissipation .power. In the field shall not exceed the rated power. If the thermistor ambient temperature of more than + 25 ° c, you must reduce its load. <br> <br> ⑦ rated working current IM: thermistor in status of the nominal value .. <br> <br> ⑧ measuring power Pc: the environmental temperature, thermistor receptor test current heating resistance changes caused by not more than 0.1% consumes power. <br> <br> ⑨ maximum voltage: for NTC thermistor, refers to the .ambient temperature, the inconvenience thermistor humped hot out of the allowed maximum continuous imposed DC voltage; for PTC thermistor, refers to the ambient temperature and the still air, which allows the imposition of consecutive to a thermistor and guarantee the thermistor working in PCT characteristics part .of maximum DC voltage. <br> <br> ⑩ the maximum operating temperature Tmax: the technical conditions, thermistor long-term continuous working the allowed maximum temperature. <br> <br> ⑾ switching temperature tb: PCT thermistor resistance value began to .increase the temperature when jumping. <br> <br> ⑿ dissipation factor H: 1 ° c increase in temperature, thermistor the dissipation of power, mW / ° c. <br> <br>.

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