| After several years of great business success, Edwin | | | | the motion of the intruder will be detected triggering |
| Holmes, the man who first made burglar alarms a | | | | the burglar alarm to sound off. An electric circuit |
| necessity to security, sold his company to the | | | | system is either a closed-circuit or an open-circuit |
| American Telephone and Telegraph Company | | | | type. In a closed-circuit, when a door is shut, the |
| (AT&T) in 1905. AT&T brought the burglar | | | | electric circuit is also closed implying that electricity is |
| alarms into the world of emergency call systems | | | | able to pass through the circuit. However, when the |
| employed by both police and fire departments, and | | | | door is ajar, the circuit becomes open, disrupting the |
| the rest, as they say, is history. | | | | electric flow, thus, activating the alarm. |
| Over the years as alarm systems became cheaper, | | | | The reverse is true for an open-type circuit system. |
| burglar alarms have become a standard feature of | | | | The burglar alarm becomes activated when the circuit |
| commercial establishments and residences. Despite | | | | is closed. |
| the increasing widespread use of burglar alarms, how | | | | How does the alarm system detect movement? This |
| many of us know how these machines actually | | | | is through the use of magnetic sensors. A magnetic |
| work? This article hopes to impart a few basic facts | | | | sensor consists of a battery serving as power |
| about burglar alarms in particular on how they work, | | | | source, a spring-switch, a magnet embedded in the |
| components of a burglar alarm system, and reasons | | | | door, and a buzzer. Once motion is detected, the |
| for investing. | | | | magnetic sensor sends signals via the control box, |
| The inner workings of burglar alarms are comparable | | | | which, in turn, transmits signals to the alarm device. |
| to a simple electric light bulb. The main difference falls | | | | The sounding off of the alarm aims to scare off the |
| on how to turn them on: a light bulb requires a | | | | intruder. There are also more sophisticated burglar |
| person to press the light switch to on while a burglar | | | | alarms equipped with control boxes that are actually |
| alarm detects movement (usually of an intruder) for | | | | linked to the police alerting the station of the intruder. |
| it to be activated. Hence, if a door is forcibly opened, | | | | |