The 555 light-off reminder principle circuit

Published:2011/6/17 1:04:00 Author:Seven | Keyword: light-off reminder, principle circuit | From:SeekIC

When the light is on, the power supply from the direction light relay is imposed on 555 8-pin, which makes the capacitor C3 charges by R1. As the charging is going on, the LEV on 6-pin is rising, when the LEV reaches 2/3VDD (after it is delayed about 1min), the 555 is reversing, 3-pin outputs a low LEV to make BG conducting. Then the LED is driven to glow, the buzzer is ringing, and the photo-sound reminds the driver of turning off the light quickly. The time of lighting, which is corresponding to the delayed time in the circuit, can be changed by adjusting the time constant R1C3.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Audio_Circuit/The_555_light_off_reminder_principle_circuit.html

Print this Page | Comments | Reading(3)