system can comprise one mix-
ture all three categories. PIR detectors and ultrasonic detectors
Definition
A movement heat detector placed
in room will detect the presence of
anyone entering leaving that room.Basic Electrical Installation Work
336
property.52
PIR detector and field detection.52.
PIR detectors are designed sense heat changes the field view dic-
tated the lens system. Light fittings must installed out reach intruder order
to prevent sabotage the security lighting system.
Intruder alarm systems
Alarm systems are now increasingly considered essential feature
of home security for all types homes and not just property high-risk
areas. Intruder alarm systems can broadly
divided into three categories those which give perimeter protection,
space protection trap protection.
FIGURE 14.
PIR detectors are often used switch tungsten halogen floodlights because,
of all available luminaires, tungsten halogen offers instant high-level illumi-
nation. 14. The field view can wide 180°, shown
by the diagram Fig.
A perimeter protection system places alarm sensors all external doors
and windows that intruder can detected she attempts
to gain access the protected property.
Definition
An intruder alarm system serves
as deterrent potential thief
and often reduces home insurance
premiums. also saves energy because the lamps are only switched when
someone approaches the protected area.
Definition
PIR detector units allow householder
to switch lighting units automati-
cally whenever the area covered is
approached moving body whose
thermal radiation differs from the
background.
A movement heat detector placed room will detect the presence of
anyone entering leaving that room.
Definition
A perimeter protection system places
alarm sensors all external doors
and windows that intruder can
be detected she attempts to
gain access the protected property. This involves fitting proximity
switches all external doors and windows.
. This capability overcomes the problem of
false alarms, and typical PIR shown Fig.53. This surprise factor often encourages the
potential intruder ‘try next door’. Many the ‘better’ detectors use split lens
system that number beams have broken before the detector
switches the security lighting. the event burglary
they alert the occupants, neighbours and officials possible criminal
act and generate fear and uncertainty the mind the intruder which
encourages more rapid departure. 14.
FIGURE 14. The major contribution secu-
rity lighting comes from the ‘unexpected’ high-level illumination area
when intruder least expects it.53
A typical PIR detector. intruder alarm system serves deterrent potential thief
and often reduces home insurance premiums
