Meter for fuel level in tank - has temp. sensitive resistor immersed in liq. and supplied with constant current

摘要

The fuel gauge incorporates a sensitive resistor with a heating system. A meter displays the resistance change caused by change of the liquid level. The temp. sensitive resistor (WI) consists of an insulating foil (3) and a metal layer (2) with a high temp. coefficient. A current source (1) is connected to this resistor. it delivers a current independent from the liquid level, and voltage drop across the resistor is the measure for the level. The insulator is typically plastics. The voltage change is measured by an indicating meter (4).