Terms and abbreviations
Contact- A NC device used to monitor a door or window for change of states.
EOLR- end of line resistor, used to supervise the wiring of
security panels and fire alarm panels.
EOLS- end of line supervision
Motion Detector-Used to detect motion inside a home or building using infrared energy, microwave technology or a combination of both, sometimes referred to as a PIR
NAC- Notification appliance circuit, used in fire alarms EX; Horns and strobe lights. EOLR is used to ensure no devices have been tampered with and will work when power is applied to them.
NC or N/C- normally closed, used to indicate the state of a
relay contact or switch, in most applications a resistor would be wired into
series with this type of device for EOLS.
NO or N/O- normally open, used to indicate the state of a relay
contact or switch, in most applications a resistor would be wired into parallel
with this type of device for EOLS.
Ohms- The measurement of how much resistance a resistor offers
to the follow of electricity. Also used in ohms law. Usually measured with a
multimeter.
Ohms law- Ohm's Law defines the relationships between (P) power, (E)
voltage, (I) current, and (R) resistance. One ohm is the resistance value
through which one volt will maintain a current of one ampere.
Parallel- Electricity has multiple paths in the circuit. Most
common in fire alarm circuits and other life safety related systems.
Series- Electricity only has one path in the circuit. Most common
in door/window switches, motion detectors and glass break sensors.
