1: Self-excited ultrasonic generator
The self-excited ultrasonic generator does not require a dedicated oscillator, and does not require a starting circuit. The high-power switch tube doubles as an oscillator tube. The ultrasonic transducer itself is a capacitive element, and an inductor is added to form a series resonance circuit. After the power is turned on, the circuit will self-oscillate, and the oscillation signal will be fed back to the high-power switching tube, which is amplified by the switching tube and then sent to the resonance circuit. The entire circuit is a closed loop. The generator generates enough power to make the transducer automatically maintain resonance. The self-excited ultrasonic generator has simple circuit, large volume, and insufficient output. It is suitable for cleaning applications of low-power generators. It can also be combined with unit circuits in parallel to drive high-power transducers.
2: Heterogeneous ultrasonic generator
Heterogeneous six-wave generator mainly includes two parts:
One is the pre-stage oscillator and the other is the post-stage power amplifier. The switching pulse of the oscillator is used to control the on and off of the switch tube, and the output transformer is coupled to transfer the ultrasonic energy to the transducer. The circuit structure of the generator is more complicated than that of the self-excited generator, but the generated signal frequency is stable, can be in a wide range of words, and the control is flexible, especially the non-stage switching output, high efficiency and high power.
In terms of performance stability and service life, the externally excited ultrasonic generator is better than the former, and it is recommended to use the latter for commercial use.