The self-switching principle is a synthesis of synchronous type switching and switch inner protection mechanisms. Both switch ON and switch OFF are performed on the base of current and voltage measurement across the switch. Applied to an active bidirectional device, it may give complete autonomy to the switch. On the basis of those principles, the synthesis of an autonomous bidirectional free-wheeling path for an AC/AC buck converter is implemented with active switches. This paper introduces the current/ voltage state representation in order to illustrate the experimental switching mechanisms. As a further application, the automatic triac is synthesized for a bipolar AC/DC half-bridge converter.