Linear Circuit of Thermistors

Published:2011/7/22 21:42:00 Author:Michel | Keyword: Thermistors, Linear | From:SeekIC

The picture is thermistors linear circuit.This circuit is also constant current source circuit and its same phase input port's benchmark voltage is provided by 78LO5.A2 output provides a constant current for thermistors RT and the current enters the ground via R1.Constant current value depends on Rl resistance. If the resistance RT is 5kΩ,the voltage on RT decreases to 0·6V and the constant current is 120 μA. The voltage is added to the VT1 source through the A3 buffer.R2's function is that it makes A3 output voltage keep constant when it flows through invalid current and VT1 source current alters.R3 voltage and temperature on two endsare linear relationship but R3 is float state.Thus,the differential amplifier A4 takes out the voltage and outputs voltage U.It and the temperature become linear relationship.



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