There are two types of vibrators for ultrasonic cleaning machines: self excitation and other excitation

The high-frequency circuit is used to convert 220V mains power into a high-frequency current of about 40 kHz to supply power to the ultrasonic vibrator. There are two types of vibrators for ultrasonic cleaning machines: self excitation and other excitation.
After the ultrasonic cleaning machine rotates the mechanical timing switch to make the power-on circuit work (when the indicator light is powered on), the 220V AC is rectified by an EMI circuit composed of RV1, C1, T1, and D7-D10, forming a DC voltage of about 300V. The 300V voltage is connected to Q2 through R3 and R4, and the current is connected to ground through R3, Q2, L3, and C3. At the same time, the current induced by L3 is applied to both ends of the oscillator through L2 and L1-1, and the current induced by L1-2 will cause Q2 to conduct further. This positive feedback process allows Q2 to quickly enter a saturated conductive state. As C3 is charged, L3 energy storage continues to increase, and the current flowing through R3 Q2 L3 continues to decrease. L1-2 L1-3 generates a reverse electromotive force. In order to prevent the decrease of current, the electromotive force quickly switches Q2 from saturated conduction to cutoff, and Q1 jumps from cutoff to saturated conduction.
At this time, the current of the ultrasonic cleaning machine reaches the ground through R3, C2, L3, and Q1. Similarly, the current induced by L3 acts on both ends of the vibrator through L2 and L1-1, and the current induced by L1-2 will further conduct Q1. This positive feedback process allows Q1 to quickly enter a saturated conductive state. As C2 charges, L3's energy storage continues to increase, and the current flowing through R3, Q1, and L3 continues to decrease. L1-2 and L1-3 generate a reverse electromotive force. To prevent a decrease in current, the electromotive force quickly changes Q1 from saturated conduction to cutoff, and Q2 from cutoff to saturated conduction. Repeat this process and the ultrasonic vibrator will not be turned off by a high-frequency current of about 40 kHz induced by L2. Stop working.
R1 and R2 in the ultrasonic cleaning machine circuit discharge the electrical energy stored in C2 and C3, making the circuit work normally in the next cycle after charging. R8 and R9 divide the voltage of+300V equally, making the voltage between the two poles of the two switch tubes CE equal. D5 and D6 are used to protect the two switch tubes from breakdown. When using, avoid objects directly contacting the bottom of the cleaning tank (inner tank), and avoid damaging the ultrasonic vibrator due to insufficient contact with liquid after ultrasonic waves are emitted from the bottom of the inner tank. In addition, the washing liquid in the tank should exceed 3/1, otherwise the ultrasonic vibrator may be easily damaged.