PHOTOMICROSENSOR OPERATION CHECK CIRCUIT AND CONTROL THEREOF

摘要

PURPOSE: To provide a photomicrosensor operation check circuit for correctly checking operation, and a control method thereof by detecting whether a failure is caused by reduction in the sensitivity due to adhesion of matters or to failure in a photomicrosensor, even when there is an adhered matter such as dust in the photomicrosensor. ;CONSTITUTION: Two transistors Q1, Q2 for controlling the supply power source in the emission side of a photomicrosensor 1 and resistances R1, R2 are provided. The output side of the resistance is connected to a light emitting diode 2 in this photomicrosensor operation check circuit. The amount of current flowing into the light emitting diode 2 is controlled by preferentially turning the transistors Q1 and Q2 on/off, and the intensity of the light of the light emitting diode 2 is thus controlled by a photomicrosensor operation check circuit.;COPYRIGHT: (C)1993,JPO&Japio