Circuit Project Electronic

A friend of me inquires about power supply switching circuit. Which produce from the People’s Republic of China model the circuit is all. Be the Chinese seek difficult many circuits. I then try to seek many circuit. Meet this circuit. Think may yes. Because of there is the Chinese controls all equipment detail. But must beg one’s pardon friends. With that model the circuit not clear however might enough in rows the profit ? A few the a little when see good as a result see equipment position understands not difficult extremely. There is the integrated circuit TL494 with and can give voltage output get +12V,-12V and +5V support using has usually.