A reliable alarm system is a major part of most security systems that are used in commercial, industrial, and residential buildings. In its basic configuration, it is just any device or contraption that sends an alerting signal whenever a pre-defined security threat is encountered. The alerting signal is usually a siren intended to notify occupants about a security threat.
Depending on the type you choose, the threat may be related to fire, burglary, or any other emergency.
In burglar alarm systems, the alerting signal is also designed to deter an intruder from further entering the secured premises as well as notifying occupants of the building about the unauthorized intrusion.
In many sophisticated models, a separate signal is also remotely sent to a local law enforcement station, or to a control or monitoring centre that is staffed by private security professionals.
Basic mechanism of burglar alarm systems
Intruder alarm systems come in a broad range of options from cheap, easily installed devices to sophisticated wireless models. The most basic type consist of just a simple electrical circuit installed in a portal such as windows and doors.
Depending on how a circuit is configured, the interruption of electrical current from one circuit terminal to another already constitutes a trigger that may be used to send of an alerting signal such as a loud siren.
In both open and closed electrical circuits, a switch is used to open and close the flow of electricity. In a closed-circuit model, electric current is allowed to flow freely from one terminal to the other. That is, the circuit is closed when a portal such as a door or window is closed.
When the door or window is opened, the circuit will be opened and the electrical current is blocked and may not flow from one terminal to the other. When this happens, the system will send of an alert signal such as a loud siren, notifying occupants and nearby residents about an unauthorized intrusion.
On the other hand, electric current in an open-circuit alarm system only flows from one terminal to the other when a portal is opened. When alarm-secured doors and windows are closed, no electrical current passes from one terminal to the others.
Some experts believe that closed-circuit models are better than open-circuit systems because determined burglars can easily deactivate open circuit systems without causing the siren to sound simply by cutting the cables.
Triggering the alarm
Security alarm systems use different ways of alerting building owners and other stakeholders of a security threat. Most models usually use a siren, flashing outdoor lights, and auto dialers or other communication devices.
Sirens and flashing lights typically alert the building occupants as well as other people within the vicinity about an unauthorized intrusion. Sirens and flashing lights may also compel intruders to immediately leave the premises.
On the other hand auto-dialers and or wireless communication devices may be used to directly notify the local police station of the security threat or it may be used to inform a private security company about the threat. Either way, a system of security protocols will determine how the unauthorized intrusion will be addressed.