Parameter: Power Supply: DC 4.5V-5.5V Frequency: 40kHz Communication: IO Level Measuring Range: 5cm – 0.8m Measuring Accuracy: 4mm Working Principle: The ultrasonic level transducer is installed vertically on the liquid surface. When the ultrasonic level transducer works, it will emit an ultrasonic pulse to the liquid surface. After a period of time, the sensor of the ultrasonic level transducer will receive a signal returned by the liquid level. The time difference between the ultrasonic level transducer transmitting and receiving ultrasonic waves, so as to calculate the distance from the liquid surface to the sensor, the specific height of the liquid level can be calculated.