CAT CAT Burglar Alarm Components & Detection 1 — Questions and Answers
Question 1: A passive infrared (PIR) motion detector works by sensing:
- Changes in radio frequency signals in the detection zone
- Changes in infrared energy emitted by warm moving bodies (Correct answer)
- Reflected ultrasonic sound waves from moving objects
- Changes in visible ambient light levels
Correct answer: Changes in infrared energy emitted by warm moving bodies
PIR detectors sense changes in infrared radiation emitted by warm bodies moving through the detection zone, triggering an alarm when a significant change is detected.
Question 2: What type of sensor uses a magnet and a reed switch mounted on a door or window frame?
- Vibration sensor
- Glass break sensor
- Magnetic contact sensor (Correct answer)
- Pressure mat sensor
Correct answer: Magnetic contact sensor
Magnetic contact sensors consist of a magnet on the movable door/window and a reed switch on the fixed frame; when the gap widens, the circuit opens and triggers an alarm.
Question 3: Up to what distance are glass break acoustic detectors typically rated to detect glass breakage?
- 5 feet
- 10 feet
- 15 feet
- 25 feet (Correct answer)
Correct answer: 25 feet
Glass break detectors are typically rated to detect glass breaking up to 25 feet away, though exact range depends on manufacturer specifications and room acoustics.
Question 4: What are the TWO primary purposes of entry and exit delay settings in a burglar alarm system?
- Reduce power consumption and extend battery life
- Allow authorized users time to enter/exit without triggering an alarm and reduce false alarms (Correct answer)
- Test the communication path and log entry events
- Enable remote arming and prevent accidental zone bypasses
Correct answer: Allow authorized users time to enter/exit without triggering an alarm and reduce false alarms
Entry/exit delays allow authorized users to arm/disarm the system within a preset time window and simultaneously reduce false alarms caused by accidental triggers.
Question 5: A dual-technology motion detector reduces false alarms by combining which two sensing technologies?
- PIR and microwave (Correct answer)
- Ultrasonic and infrared thermography
- Laser grid and radar
- Camera imaging and PIR
Correct answer: PIR and microwave
Dual-technology detectors combine PIR and microwave sensing, requiring both technologies to detect motion simultaneously before triggering an alarm, greatly reducing false alarms.
Question 6: What does a 'normally closed' (NC) alarm contact mean?
- The circuit is open (broken) when the device is undisturbed
- The circuit is complete (closed) when the device is undisturbed (Correct answer)
- The device requires a key to change its state
- The device only activates when externally powered
Correct answer: The circuit is complete (closed) when the device is undisturbed
A normally closed contact maintains a complete circuit in its resting state; disturbing the device (such as opening a door) breaks the circuit and signals an alarm condition.
CAT CAT Burglar Alarm Components & Detection 1
A passive infrared (PIR) motion detector works by sensing: