1, high frequency: high frequency can provide higher energy density and shorter pulse width, which is suitable for more fine and high-precision material welding, such as electronic components, micro-devices, jewelry or medical devices.

2. Low frequency: Low frequency provides greater heat input and deep welding capability, and is suitable for large parts or applications requiring deep welding, such as welding automobile parts, aviation parts or metal structures.

3. Intermediate frequency: Intermediate frequency can provide better balance performance and is suitable for various welding requirements and different types of metals, such as stainless steel, aluminum and copper.