How do real alarm systems work?
→ They operate in pretty much the same
way as the system you built: during a break-
in, a burglar will trip a hidden switch, which
will break a circuit, thereby triggering the
alarm. The circuit in an alarm system is
called a “zone.” Such switches are located
around windows and doors. If a burglar
opens the window or door, it will sound a
siren or an alarm light will go on.
Well protected
→ Today, electronic alarm systems protect
many valuable objects, such as cars, and
buildings, such as banks and apartments. A
loud siren or a wildly flashing alarm light will
usually drive off an intruder pretty quickly,
because it attracts a lot of attention.
Intruders can often even be frightened just by
seeing that an alarm system has been installed.
Holdup alarm systems serve to respond to
break-ins or notify a security service or the
police in case of a stickup.
Access control
There are also other methods,
though, to deny access to
unwanted persons. This kind of
system only lets people into a
building if
they know
the right key
combination.
CHECK IT OUT
Alarm Systems
In spite of common notions of
“night-time visitors,” well over a
third of all home break-ins happen
during the day, when people are
away from home at work or school.
Most daytime home break-ins
happen in cities.
Door switch
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