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• C. SCREENS​ -

  • Openings such as vents, ducts, skylights, and similar openings can be alarmed by thin wire filaments that signal an alarm if the screen is cut or broken. Often the wire filaments are placed in a frame of wooden rods and require little maintenance.​
• D. GLASS BREAKAGE ​(TUNED FREQUENCY)​ -

  • Miniature electronic circuits are bonded to the glass surface. They detect a high-frequency sound pattern within the glass when it is broken.​

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  • usually use a microphone, which monitors any noise or vibrations coming from the glass​
• E. Glass Breakage (Inertia)​ -

  • A device attached to window or doorframes protects multiple-pane areas. This device detects the shock wave a substantial impact against the surface makes.​
• VOLUMETRIC​ -

  • Volumetric protection sensors are designed to detect the presence or actions of an intruder almost anywhere within an entire room, from floor to ceiling.​
  • A variety of volumetric devices are available. Each kind of detector has advantages and limitations. Therefore, a device must be selected for a specific environment. ​
• VOLUMETRIC​ -

  • A major advantage is that they provide a highly sensitive and invisible means of detection in high risk areas.​
  • A major disadvantage is that an improper application can result in frequent false alarms.
• A. Infrared​ - Passive infrared sensors are part of the motion-detection group.​
• A. Infrared​ - They sense the body heat of an intruder as he passes through the protected area. ​
• A. Infrared​ - Infrared detectors are relatively free of false alarms and are highly recommended.​
• B. Ultrasonic​ -

  • Ultrasonic motion detectors generate a high frequency of sound that is out of the normal range of human being.
• C. Microwave​ -

  • This kind of motion detector uses a high frequency radio waves, or microwaves, to detect movement.​
  • It penetrates such as glass, and metal objects reflect them, they can detect motion outside the protection area causing false alarm problems if not properly installed.​
• D. PHOTOELECTRIC​ -

  • It is a device that transmit a beam across a protected area. ​
  • When an intruder interrupts this beam, the  circuit is disrupted causing an alarm.​
  • Today’s photoelectric devices use diodes that emit an invisible infrared light and usually pulses rapidly to prevent compromise by substitution.​
• D. PHOTOELECTRIC​ -

  • A disadvantage is that they an be defeated relatively easily; the beams are narrow and may be discovered or avoided.​
• 3. PROXIMITY​ -

  • Object protection provides direct security for individual items.​
• A. CAPACITANCE​ -

  • A device used to protect specific objects such as security containers and safes. The capacitance alarm uses the metal construction of the container and causes it to act as a capacitor or condenser.​
• A. CAPACITANCE​ -

  • When a change occurs in the electromagnetic field surrounding the metal object, the balance is disturbed and the alarm is activated.
• B. VIBRATION​ -

  • These seismic sensing devices use a piezoelectric crystal or microphone to detect the sound pattern that a hammer-like impact on a rigid surface would generate.​
• CONTROL UNIT​ - It regulates the entire system, turn an alarm system on and off, and transmit the alarm signal to human
• CONTROL UNIT​ -

  • With local systems, the user is responsible for turning the alarm on and off. ​
  • ​
• CONTROL UNIT - The central station and proprietary systems shift responsibility for verifying that the system is on or off from the user to the central station, and proprietary.
• Control Unit

  • The method for controlling the alarm system is usually key or digital keypad inside the premises to avoid tampering.
• Control Unit

  • It regulates the entire system, turn an alarm system on and off, and transmit the alarm signal to an annunciator.​​
• Control Unit

  • The alarm system is delayed briefly to allow the user to gain access to the system without initiating an alarm.​​
• Ultrasonic devices are prone to false alarms due to excessive air currents or ultrasonic noise form mechanical equipment.​​
• Ultrasonic

  • An intruder disrupting the ultrasonic wave pattern initiates the alarm.​
• Capacitance

  • The system can only be applied to ungrounded equipment and accidental alarms can occur if the container is carelessly touched when the alarm is activated.​​
• Vibration

  • These devices are attached directly to safes and filing cabinets, or to the walls, ceiling, and floor of vaults. False alarms may occur with these devices by passing vehicles or falling objects. ​