Radiation thermometer circuit

Published:2011/4/8 2:46:00 Author:Nicole | Keyword: radiation thermometer | From:SeekIC

The detecting element is lead sulfide photosensitive resistance, it can measure the surface temperature more than 100℃. TR1~TR3 are 3 stage amplifiers, they are fixed on the detector, through bootstrap function of bias circuit, match input to 300kΩ resistance of radiation detecting element(6ISV). Adding bias voltage to all levels, to minimize the noise. When enviroment temperature rises, the thermistor with 2kΩ NTC adjusts gain, to make up for the reduction of radiation detecting element sensitivity. Final follower drives main amplifier and indication ammeter(no gave). Radiation detecting element outputs 0.3mV, can obtain 1mV through preamplifier, main amplifier outputs 20mV, it has 10% partial difference in the most sensitive range of 200μA ammeter. This circuit has 5 measuring ranges, the range of measuring temperature is 100~500℃.



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