| 摘要 |
PURPOSE:To decide a broken light emitting element speedily and accurately by flowing a current to a visible light emitting diode coupled with the broken infrared light emitting diode and displaying the breakdown, and allowing only the photodetecting element of a photosensor to generate a photodetection output. CONSTITUTION:This device consists of the infrared light emitting diode 10, visible light emitting diode 11, photodetecting element 12, and photosensor 13. Couples of the diode 10 and diode 11 connected in parallel are connected in series. The diode 10 is lower in forward voltage than the diode 11 and the current flows through sides of the diodes 10 and flows none of the diodes 11 unless the diodes 10 are broken to open the circuit. If a coupled diode 10 breaks, the current flows through the sides of the diodes 11 and flows the parallel circuit of the diodes 10 and 11, so that the current flows through the diodes 10 whose forward voltages are lower. When the current flows through the diode 11, visible LED turns on to display the breakdown of the diode 10. |
