Security Alarms
Security alarms come in many different styles. Here are
some examples of their different types:
•Circuit alarms – These utilize an electric current running
between two points. If this current is disrupted (through the opening
of a door or window, for instance) an alarm will go off.
•Radar-based security alarms – With the use of this system,
a box regularly shoots microwave radio energy over an area. It then
waits for the waves to come back. If something disrupts the return of
the waves, then an alarm will be sounded.
•Passive infrared (PIR) security alarms – These are the
most advanced forms. While radar-based options transmit their own energy,
this system monitors the existing infrared energy of the room.