| 摘要 |
PURPOSE:To make the secular change of a light emitting element small, by detecting conduction of a photo-Triac to turn off the triggerring light emitting element. CONSTITUTION:When a photo-Triac 4 is triggerred by a light emitting element 3 and is made conductive. One of light emitting elements 12 and 14 emits the light to turn on a phototransistor 11. Consequently, a transistor 6 is turned off, and a current is not supplied to the light emitting element 3. When an AC powr source 8 approaches the zero point, currents are not supplied to light emitting elements 12 and 14, and the transistor 6 is turned on, and the light emitting element 3 triggers the photo-Triac 4 again to continue conduction. |
