CONVERTER FOR DETECTING LIQUID LEVEL AND LIQUID LEVEL DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a converter for detecting a liquid level which can stably detect the liquid level over a wide temperature range. SOLUTION: A hot side sensor 1 is connected to a constant current circuit 4 connected in series with a trimmer resistor 3 for adjustment. A voltage VH of a connection point is outputted via a buffer 6 of a gain 1 to a negative side input of a comparator 7. A voltage VC of a connection point between a cool side sensor 2 and a constant current circuit 5 is inputted to an amplifier 8 of a gain (g). To an output voltage gVC of the amplifier 8 is sent a constant current IR from a constant current circuit 9 via a resistor 10. The resistor 10 level shifts the output voltage by VR=IRR. A voltage of a connection point between the resistor 10 and the constant current circuit 9 is supplied as a voltage of an operating point (VOP=gVC+IRR) to a positive side input terminal of the comparator 7.