RF admittance level switch, its measurement principle is: RF admittance is a new type of level control technology developed from capacitive, with anti-clogging, higher reliability, accuracy, and broader applicability, being an upgrade of capacitive level technology. RF admittance, where admittance refers to the reciprocal of impedance in electrical terms, is composed of resistive, capacitive, and inductive components. RF, standing for radio frequency, refers to the high-frequency radio wave spectrum, thus RF admittance can be understood as measuring admittance using high-frequency radio waves. During operation, the sensor of the instrument forms an admittance value with the container wall and the medium being measured. As the level changes, the admittance value changes accordingly, and the circuit unit converts the measured admittance value into a level signal for output, achieving level measurement.