An ultrasonic generator is a power supply that converts an alternating current of 220V or 380V into an electrical oscillation signal at ultrasonic frequency, it is composed of an oscillator, a voltage amplifier, a power amplifier and an output transformer. In order to ensure the frequency stability of the ultrasonic generator and the impedance matching between the generator and the transducer, the ultrasonic generator is also equipped with an acoustic tracking circuit and an automatic frequency tracking circuit.
The development of ultrasonic generator is closely related to the development of electronic equipment. To some extent, the development of electronic vehicle leads the development direction of ultrasonic generator. There are many kinds of ultrasonic generators, which can be divided into analog circuit and digital circuit according to the different working principles Depending on the type of power transistor used, it can be further divided into three stages of development: the electronic tube, the transistor and the Analog chip.

                                                                                                                         

1. Electronic tube type ultrasonic generator
There are two types of self-excited and other-excited, and self-excited can be divided into automatic frequency tracking and acoustic tracking two. As early as the 1950s electronic tube has been introduced, its circuit type is simple, dynamic range, but large size, power consumption is also large, has now been eliminated.
2. Transistor type ultrasonic generator
It can be divided into two stages: analog transistor and switching transistor. The development of transistor type is attributed to the improvement of high-power devices and the development of technology. Analog transistor type, mature circuit, small output power, long life, low cost, in low power applications (less than 200W) more widely. Switching transistor, combined with IC circuit type after the circuit type simplification, output power, small size, small power, and can be easily combined with microprocessors, become the mainstream direction of development.
3. A Analog chip ultrasonic generator
Compared with the transistor type, the Analog chip type ultrasonic generator has two obvious advantages: first, it reduces the working voltage of the transducer greatly when the generator outputs low power. The operating voltage of the transducer reaches 148V at low power output of the transistor-type generator, but only 9v at low power output of the Analog chip-type generator. Second, the harmonic distortion of a Analog chip generator is significantly less than that of a transistor under the same operating conditions.
At present, the digital control of the ultrasonic generator has also come out, marking the ultrasonic generator to the intelligent development of a big step. The ultrasonic generator can be used to realize automatic storage of running data and automatic fault diagnosis by challenging control schemes and realizing many new control strategies in program software.