| 摘要 |
PURPOSE:To obtain the sure judgement of the timing of lighting in a tunnel or at the time of sunset by using a photoelectric conversion element for an automatic lighting device or the like in a car or the like. CONSTITUTION:In an illuminated tunnel, since a number of sodium lamps are used and lit by AC, the output of a photoelectric conversion element 1 contains AC compoents, and the AC component output of an AC component separator 3 is sent out. Then, the output amplified, rectified, and smoothed, is introduced into the base of a transistor 11 via a diode 8 to give continuity to the transistor 11, and a relay 12 is on to close a contact 12A for lighting. Meanwhile, for running at night, the output signal from the photoelectric conversion element 1 is very small and the output of an amplifier 6 is also smaller than the reference voltage. Consequently, the output of a comparator 7 is brought to H-level, and the transistor 11 is given continuity for lighting. |
