The investigation and design of the digital control circuits and its functions in the 6 kV cell series multi-level high voltage frequency inverter was focused on.

It didn't come up to the nation discharge standard of effluent that of the treatment of printed circuit board wastewater with coagulant sedimentation.

In this paper, combining the typical application circuit of MC33370、TOPSwitch-FX family single-chip switching power, the design methods and noticed problems of two printed circuits are introduced in detail.

This paper analyses the sources of common interference in electronic instruments and discusses the anti jamming techniques for hardware,software,printed circuit board,etc in terms of application.

By reducing bromine content and adding aluminum hydroxide in the surface of substrate for the printed circuit board,comparative tracking index(CTI)of the substrate is improved sigˉnificantly,meanwhile the size stability,heat resistance,the glass transition temperature of the substrate are improved too.