Thermometer of Transistor Temperature Sensor

Published:2011/7/11 7:40:00 Author:Michel | Keyword: Transistor Temperature Sensor, Thermometer | From:SeekIC

The picture is the thermometer of transistor temperature sensor. In the circuit,VT1 is transistor temperature sensor.A1 uses LM305 as voltage regulation circuit and it provides constant base current for VT1.When LM305 works in the condition that feet 6 feedback input voltage is 1.8V constantly and it is connected to VT1 base and emitter via R2 and Rz keeps the base current constant.R1/R2's change is the change of A1 output voltage.Because there is + lOmV / ℃ temperature characteristics when the output voltage of the LM305 outputs +5V and the same LM305 are used to compensate. The ammeter instruction is 0 if the RP2 is adjusted to -20℃ and the ammeter instruction is 100μA when RP1 is regulated to +80℃.



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