What is a Burglar Alarm Circuit?

Posted on December 5th, 2007 in Alarm Kits by Alarm

A simple electric circuit built into an entry way is what makes a basic burglar alarm work. The electricity in a burglar alarm circuit starts to flow when a channel is provided between two points of opposite charges. By either opening or closing the circuit, the electricity is turned on or off. Electrically operated appliances are turned on or off by flicking the switch. A burglar alarm sounds off when its sensors detect intrusion into an entry point of a house like a window or a door.

A burglar alarm circuit can be classified into two general categories. The first is the closed-circuit system which means that the circuit is close when the entry way like a door is shut and that the electricity continues to flow as long as the door remains shut. The alarm is trigger off the moment the door is opened and the electrical circuit is cut off. The second is the open-circuit system which basically switches on the electricity by completing the circuit once the door is opened. A burglar alarm circuit of the open-system type can easily be rendered inutile by any intruder by cutting the connecting wires that is why closed-circuit systems are generally the better choice.

There are many ways of building a burglar alarm circuit into an entry way. A simple device makes use of an electromagnetic switch that is turned on and triggers the alarm once the door or window is opened. Another simple switch is a button that is positioned between the door and the door jamb. The alarms does not sound off for so long as the door or window is close, but once it is opened the button is released and sounds off the alarm. These switches are flawed in the sense that the burglar can turn off the alarm by merely closing the door or window.

The effective burglar alarm circuit incorporates a control box that monitors the electrical circuits positioned in various entry points. Once it detects a change in the electrical circuits it sounds off the alarm continuously until the homeowner types in the security code on the control box keypad. Often times, these control boxes are hidden from view so that the intruder will not be able to find and disable it. A burglar alarm circuit in modern systems makes use of thin foil wires that run through window panes, metal strip triggers underneath mats and carpeting and other innovative high-tech triggers like motion detectors and infra-red sensors.

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One Response to 'What is a Burglar Alarm Circuit?'

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  1. venkata karthik said,

    on July 18th, 2008 at 12:43 pm

    your site is excelent………please mail me some interesting simple circuits which i can prepare ina normal lab……

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