Piezoelectric high material level automatic control and alarm circuit

As shown in the figure, the circuit is composed of a piezoelectric material level sensor, a relay control circuit, an analog sound circuit and an AC step-down rectifier circuit. When the material level rises to the set high material level position, the circuit can emit a given simulation sound and simultaneously cut off the power supply of the feeding equipment to stop the feeding and ensure safe operation. IC1 is a piezoelectric material level sensing integrated circuit. It consists of a self-excited oscillator, a rectifier circuit, a voltage comparison circuit and an open-circuit output stage. The following figure shows its internal circuit: