| 摘要 |
PURPOSE:To enable a lighting condition to be adjusted in a multi-step, and arbitrary brightness to be selected, depending upon the service condition of a lighting lamp by changing the output level of a dimmer light selector circuit. CONSTITUTION:ACD circuits 7 and 8 inserted between a lighting frequency control circuit 9 and a switching element Q1, and between another lighting frequency control circuit 10 and a switching element Q2 are fed with a control signal from a dimmer light selector circuit 11, thereby controlling the operation and non-operation of the elements Q1 and Q2. Also, the circuit 11 supplies a control signal for keeping the circuits 9 and 10 in dimmer state via lines 12 and 13, and changes the lighting frequency of lighting lamps 5 and 6 in dimmer state from the lighting frequency in full lighting state. For example, when the lines 12 and 13 are at 'H' level, the circuits 9 and 10 output a switching pulse signal having a lighting frequency for full lighting state. |
