How Do They Work?

Burglar alarms are used throughout the United States, people know what burglar alarms are and what they are used for. Nevertheless they may not know how they operate. Let’s see how this protection system works in detail.

Burglar alarms are a simple electric circuit. To open or close a light, you simply throw a switch. In a Burglar alarm it’s the same except the switch detects the movements of the intruder such as the opening a door or window.

In a closed-circuit system, the electric circuit is closed when the door is shut. This means that as long as the door is closed, electricity can flow from one end of the circuit to the other. But if somebody opens the door, the circuit is opened, and electricity can't flow. This triggers an alarm.

In an open-circuit system, opening the door closes the circuit, so electricity begins to flow. Also in this system, the alarm is triggered when the circuit is completed.

• a battery powering a circuit
• a spring-driven metal switch built into a door frame
• a magnet embedded in the door, lined up with the switch
• a separately-powered buzzer with a relay-driven switch.

The control box is hooked up to one or more alarm circuits, but it also has its own power supply. Once the alarm is triggered, the control box won't cut it off until somebody enters a security code at a connected keypad. In most installations the control box is kept in a veered place so that the burglar can't even think of disabling it when the alarm goes off.