Capacitive liquid level sensor is used widely in industry

agriculture

health care and other fields due to its low price and simple structure.However

because the dielectric constant of the media should be gained before measurement and this constant must be calibrated periodically

its application is restricted greatly.Based on the analysis of the problems existing in the present capacitive liquid level measurement

two parallel plate capacitors with right-angled triangle shape and same structural parameters

which symmetrically aligned in the same height

are utilized as liquid level sensor at the same time.The differential method is adopted to eliminate the influence of the dielectric constant to the measurement and the medium-independent capacitive liquid level measurement is implemented.The experiments of pure water and gasoline show the validity of this method.