| Home Security System are used throughout the | | | | system, The Alarm is triggered when the circuit is |
| United States, people know what Burglar alarms are | | | | completed. |
| and what they are used for. Nevertheless they may | | | | Magnetic sensor |
| not know how they operate. Let?s see how this | | | | A magnetic sensor in a closed circuit consists of a |
| protection system works in detail. | | | | few simple components. |
| The Circuit | | | | - a battery powering a circuit |
| Home Security Systems are a simple electric circuit. | | | | - a spring-driven metal switch built into a door frame |
| To open or close a light, you simply throw a switch. | | | | - a magnet embedded in the door, lined up with the |
| In a burglar alarm it?s the same except the switch | | | | switch |
| detects the movements of the intruder such as the | | | | - a separately-powered buzzer with a relay-driven |
| opening a door or window. | | | | switch. |
| Two categories | | | | Control box |
| In a closed-circuit system, the electric circuit is closed | | | | The control box is hooked up to one or more alarm |
| when the door is shut. This means that as long as | | | | circuits, but it also has its own power supply. Once |
| the door is closed, electricity can flow from one end | | | | the alarm is triggered, the control box won't cut it |
| of the circuit to the other. But if somebody opens | | | | off until somebody enters a security code at a |
| the door, the circuit is opened, and electricity can't | | | | connected keypad. In most installations the control |
| flow. This triggers an alarm. | | | | box is kept in a veered place so that the burglar |
| In an open-circuit system, opening the door closes | | | | can't even think of disabling it then the alarm goes |
| the circuit, so electricity begins to flow. Also in this | | | | off. |