| 摘要 |
<p>PURPOSE:To correct a decrease in a light output of a light emitting element even if the light output characteristics of the light emitting element are deteriorated and to facilitate the design of a peripheral circuit by providing a phototransistor in which its current varies in response to the intensity of a light upon reception of part of the light of the light emitting element in parallel with the light emitting element. CONSTITUTION:A light emitting diode 1 which emits a light in response to a voltage applied between input terminals TI1 and TI2, a phototransistor 2 connected in parallel with the diode 1 and in which a current IC flowing in response to the intensity of a light varies upon reception of part of a light emitted from the light emitting diode 1, and a phototransistor 3 which outputs an electric signal in response to the intensity of the light received from the light emitting diode are provided, all sealed in one vessel 4 to form a photocoupler. Here, when the light output of the light emitting diode 1 is reduced, the current IC flowing to the phototransistor 2 is decreased, but since an input current IIN is constant, a current corresponding to a reduction in the current IC flowing to the phototransistor 2 flow to the light emitting diode 1 to increase an emitting light output. Thus, the deterioration of the emitting light output characteristics of the light emitting element is corrected to facilitate the design of a peripheral circuit.</p> |
