MAINTAINED CONTACT SWITCH: switch designed for applications requiring sustained contact, but with provision for resting

MAKE: to close or establish an electrical circuit

MANTRAP: see interlock

MAXIMUM RATING: absolute maximum condition in which a device is designed to operate; voltage, frequency, current, temperature, humidity, shock, and other parameters can be specified as maximum

MILLIAMPERE: one one-thousandth (0.001) of an ampere

MILLISECOND: one one-thousandth (0.001) of a second

MODE OF OPERATION: specified operational condition of a switch, lock, door system, etc.

MOMENTARY DUTY LOCK: electric lock equipped with a solenoid that is energized only momentarily

MOMENTARY LOSS OF POWER: short interruption of power to the total equipment

MOMENTARY SWITCH: spring-loaded contact that, when pressed, closes two contacts; when pressure is removed, contacts open

MONITORING LOOP: continuous loop of wire starting at the control panel and running through switches in a system to indicate a breach of security through an open switch or a cut wire

MOTHER BOARD: master printed circuit board used to interface activities of individual printed circuit boards and the devices being controlled or monitored; the mother board is usually located at the back of a control panel assembly; individual printed circuit boards plug into it 

NATIONAL ELECTRICAL CODE (NEC): (1) consensus standard published by the National Fire Protection Association (NFPA) (2) commonly called “code”

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA): organization known for its standardization of wire and cable specifications

NOISE: unwanted and/or unintelligible signals picked up on a cable circuit

NORMALLY CLOSED (NC): condition or position of a contact prior to initiation or energization— in this case a closed condition

NORMALLY OPEN (NO): condition or position of a contact prior to initiation or energization— in this case, an open condition

OPERATING VOLTAGE: (1) voltage by which a system operates (2) nominal voltage with a specified tolerance applied; design voltage range necessary to remain within the operating tolerances; for example, for a system specified 120 volts +/-10 percent of nominal, 120 volts is the nominal voltage and the design voltage range is 108 to 132 volts AC

OUTPUT VOLTAGE: designed power source produced by a power supply

POTENTIOMETER (pot): variable resistor

PRIMARY: transformer winding that receives the energy from a supply circuit

PRINTED CIRCUIT BOARD: means of making electrical interconnections without using insulated wires; printed circuit boards provide a supporting and insulating medium for components and conductors in a form that is readily adaptable to machine assembly

RATED VOLTAGE: maximum voltage at which electric component can operate for extended periods without undue degradation or safety hazard

RECTIFIER: solid state electrical device that will allow current to flow in one direction only; it is designed to convert alternating current to direct current

RECYCLE TIME: time needed to reset and re-initiate the timing function and remain within the specified timing tolerances; generally specified “during timing” or “after timing”

REGULATED POWER SUPPLY: power supply that provides a constant output regardless of input voltage variations

RELAY: electrically controlled-device that opens and closes electrical contacts to effect the operation of other devices in the same or another electrical circuit

REMOTE ALARM: visual or audible signaling device used to signal violations at locations removed from the central control station or monitored openings; for example, a remote alarm may be placed on a roof, or at guard stations outside a building

REMOTE RESET: switch located at a monitored opening; if a violation occurs, the alarm at the main control console cannot be turned off until the door is secured and the remote reset is activated; its purpose is to ensure the inspection of an opening that has been violated or left open

RESET TIME: time required to return the output to its original condition

RESISTANCE: (1) opposition to flow of an electric current (measured in ohms) (2) reciprocal of conductance

RESISTOR: circuit element whose chief purpose is to oppose the flow of current

SALLY PORTS: see interlock

SECONDARY: transformer winding that receives energy by electromagnetic induction from primary

SECURITY CONDITION SENSOR (SCS): sensitive crystal relay to operate the LED with an SPDT switch to indicate low voltage and tampering of the lock face locally or to a remote monitoring location; primarily used in higher security applications

SECURITY INTERLOCK: multidoor system in which all doors are normally closed and locked; releasing one door disables the releases for all other doors until the first door is closed and relocked

SHORT: improper connection between “hot” current-carrying wire and neutral or ground

SINGLE POLE, DOUBLE THROW (SPDT): switch or relay contact form (1 form C) that has a normally open and a normally closed contact with a common connection

SINGLE POLE, SINGLE THROW (SPST): switch with only one moving and one stationary contact, available either normally open (NO) or normally closed (NC)

SOLENOID: (1) electromechanical device that operates the lockbolt (2) when electricity is applied, a mechanical device

SPIKE: momentary increase in electrical current; spikes can damage electronic equipment

SWITCHES: devices that make or break connections in an electrical or electronic circuit; switches are usually manually operated but can also work by mechanical, thermal, electromechanical, barometric, hydraulic, or gravitational means

SWITCH, MAINTAINED: switch that, when activated, maintains its activated position until it is inactivated

SWITCH, MOMENTARY: see momentary switch

SWITCH, NORMALLY CLOSED: see normally closed

SWITCH, NORMALLY OPEN: see normally opened