Mains synchronised electronic switching circuit - is for e.g. lighting device, combines switch signal with output of zero transition detector

摘要

The switching circuit for an AC load circuit uses an AND-gate receiving the output of a zero transition detector in conjunction with the output of a storage stage coupled to a touch-control switch. The output of the AND-gate controls a power stage for switching the AC load circuit. Pref. the zero transition detector uses a pair of similar transistors in common collector configuration with their bases coupled to respective supply terminals directly and via a voltage divider. The switching circuit can be used for a lighting device and prevents flicker.PS.