| Security Components |
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Security systems include switches, sensors, auditory monitors, and controllers. Most security systems have at least two of these components. Switch circuits are either open or closed. A switch on a closed window or door is closed; if the window or door is opened the switch is open. The controller continuously checks to see if each switch is open or closed and, if open, sets off the alarm. There are various types of sensors, but they all work similar to a switch. They are either OK or not OK. For example, a smoke detector is OK until it senses smoke, then it is not OK and sets off an alarm. Motion sensors are OK if nothing moves in its sensory area; movement triggers the alarm. Vibration sensors work the same way, attached to window glass. The control panel is the brain of the operation. All switches and sensors report to it frequently. The control panel decides what to do with any open or not OK reports. Actually, it only follows the orders of whoever set it up: If open, call 9-1-1 or If not OK, sound alarm.
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