Dimmer switch for lighting, comprises chopping transistors and microcomputer which enable a lighting load to be run at low voltage and voltage peaks to be counted to determine mode of operation

摘要

An electrical load (10) typically lighting is supplied from an alternating current source (CA) through a transistor chopping circuit (11,11a) which is part of a dimming switch (12). The dimmer switch includes a microcomputer (13) and a synchronizing circuit (15) which enable the load to be run initially at low voltage, peaks counted and if above a threshold normal operation to be changed from open phase to closed phase