| 摘要 |
PURPOSE:To eliminate fluctuation of a continuous angle caused by fluctuation of a trigger voltage by temperature and eliminate fluctuation of brightness or malfunction by using a transistor for a switching element for putting the control electrode of a thyrister at a predetermined potential. CONSTITUTION:In a dimmer circuit in which a full-wave rectified voltage is applied to a luminescence element 2 and this current is adjusted in a thyrister 3, a sequential circuit 6 generates a predetermined voltage at a plurality of output terminals sequentially by inputting a clock, for example, for a switching signal of a switch, and it is controlled by means 7, 8 to give these outputs to the control electrode of the thyrister 3 and signals from the other output terminals of the sequential circuit 6, and is provided with a switching element 9 to put the control electrode of the thyrister 3 at a predetermined potential. For the transistor 9, a saturation range and a cutoff range are only used for the switching element. If the temperature of the substrate changes, therefore, the temperature characteristics of the transistor 9 is not related with the continuous angle of the thyrister 3. |
