Car Burglar Alarm timer alarm system circuit , model to economize. This circuit convenients for to set up in an automobile. usually switch at set up keep with automobile door will the circuit closes. But in case of car owner opens in and out while note as a result have no result anything , because of the transistor model PNP to still don’t work. Because of 9 pin have high voltage.
But when switch the door any one open the circuit exceed time delay keep 5 pin of IC NE556 have low voltage to fully drive transistor circuit give relay work. The system will order to give the horn a car talks at one time to come to immediately. But if we shut the door a car or close S1 system stop work again.
Alarm Sound With Control Switch
The heart of this circuit is IC No. 555. When the alert sound was working, even though the switch will continue to be the same, the sound still does not stop immediately.But it will stops automatically, when a set time period,Depending on the resistance of R3, the circuit so I set a time period equal to 1M for 1 minute 6 seconds.
The output of IC 555 is triggered by a positive voltage on pin 2,when all switches are connected together.When the something switch is cut off pin 2, it will be negative voltage and the trigger IC 555 will stop. The C1, C4 to protects a noise signal from either switch, which may cause the alarm to be up. This circuit can be used with power supply from 5V to 15V depending on relay sure enough.
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