light off reminder circuit composed of 555

Published:2011/5/4 9:28:00 Author:TaoXi | Keyword: light off, remind | From:SeekIC

The light off reminder circuit composed of 555 is as shown. This circuit is composed of the monostable delay circuit, drive circuit, buzzer, LED.etc. The output signal of the monostable delay circuit which is composed of the 555 and R1、C3 control the other circuits. After turned on the light, power of the direction light relay adds to the pin-8 of 555 by diode, so the capacitor C3 is charged by R1. Pin-6's electric potential increases, when the pin-6's electric potential increases to 2/3VDD, 555 overturns and pin-3's output low-level voltage makes BG turn on. And this low-level voltage drives the LED to turn on to remind the driver turns off the light.



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