| 摘要 |
PURPOSE:To keep the illuminance constant with no manual operation by providing a control means which complies with the control command of the luminous quantity or controls the luminous quantity to make the detection value of an illuminance detecting means constant. CONSTITUTION:When the automatic control mode is first released by a mode selecting switch 14 then a luminous quantity selecting knob 12 is operated, a processor 17 transfers the digital voltage value fed from a D/A converting circuit 16a to a D/A converting circuit 18, the fed power source voltage is increased or decreased to adjust the luminous quantity of a table lamp. When the desired illuminance is attained, the automatic control mode is selected by a control mode selecting switch 14. The processor 17 stores the digital voltage value indicating the illuminance fed from an illuminance sensor 13 in its built-in register then reads the output of an A/D converting circuit 16b at the preset cycle and increases or decreases the digital voltage value fed to the D/A converting circuit 18 to make it equal to the digital voltage value stored in the register. The illuminance can be automatically controlled without repeating the troublesome manual operation. |
