555 fridge door-closing reminder circuit (2)

Published:2011/6/16 6:20:00 Author:TaoXi | Keyword: 555, fridge, door-closing, reminder | From:SeekIC

As the figure 13-2 shows, the reminder is composed of the monostable delay circuit which is composed of the 555, C1, RP and a KD-9300 music IC2. When you open the door, the switch AN is pressed, the 6V power adds to the 555, because the voltage of capacitor C1 can not be changed, so pin-2 has the high electric potential to make the 555 to output the low electrical level. After the delay time of 0 to 2 minutes, the circuit sets, IC2 gets the power to send out the sound of music. After you close the door, AN is unclinched, you can change the delay time by adjusting RP.



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