| 摘要 |
PURPOSE:To prevent an error lighting of a luminous lamp by providing a suppression circuit to suppress the lighting of the luminous lamp temporarily when the surrounding brightness is converted from bright to dark, or from dark to bright. CONSTITUTION:When the surrounding brightness is changed from bright to dark, for example, the output of the inverter I6 of a brightness detecting sensor 7 is turned to 'L' to turn on a transistor Q5, a power source Vop for operation amplifier is output, and a human body detection process circuit is set to the operation condition. In this case, a noise signal is output from an amplifier detector circuit 2a resulting from an unstable standard voltage of an operation amplifier OP2. However, since a transistor Q6 of a suppression circuit 8 is turned off in a specific time set by a resistance R5 and a capacitor C5, the base of a transistor Q3b is turned to 'H' forcibly, and the lighting of a luminous lamp 4 by the noise signal is prevented. Consequently, when the surrounding brightness is changed from bright to dark, for example, an error operation such as the unnecessary lighting of the luminous lamp 4 can be prevented. |
