JPS6343993B

PURPOSE:To enable to perform change-over between bright illumination and faintly lighted illumination by a method wherein a TRIAC is controlled by ON-OFF action of an input commercial electric power source. CONSTITUTION:The control voltage of a phase control circut CS for regulation of light using the TRIAC5 is changed by repetition of ON and OFF of the commercial AC electric power source to be inputted to make the control angle of the phase control circuit for regulation of light to be chaged to regulate electric power to be applied to a lamp load 4 optionally, and timer mechaisms 18, 19 are assembled in the control circuit CS to regulate optionally electric power to be applied to the load 4 automatically after the prescried time from ON of the input electric power source, and a light emitting device 17 to indicate clearly operating condition of change- over of switch is annexed. Accordingly because it can be made as to be lighted brightly during the time when visitors came in evening, and to be faintly lighted automatically after the prescribed time, saving of electricity can be attained, and moreover lighting condition can be indicated.