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A circuit diagram (or: wiring diagram, electrical diagram, elementary diagram, electronic schematic) is a graphical representation of an electrical circuit. A pictorial circuit diagram uses simple images of components, while a schematic diagram shows the components and interconnections of the circuit using standardized symbolic representations.
The NFPA 72 standard uses the term Alarm Box, which could encompass a number of initiation mechanisms. [3] A few manual call points have been approved to UL/UL Canada standards. [4] [5] At the time of this writing, the pull station is still the most prominent design in this part of the world.
From NFPA 72, 2002 Edition: “7.4.2.1* To ensure that audible public mode signals are clearly heard, unless otherwise permitted by 7.4.2.2 through 7.4.2.5, they shall have a sound level at least 15 dB above the average ambient sound level or 5 dB above the maximum sound level having a duration of at least 60 seconds, whichever is greater ...
Exterior alarm bell box. If a potential intruder tries to enter into a house, she or he tests whether it is closed and locked, uses tools on openings, or/and applies pressure, creating low-frequency sound vibrations. Before the intruder breaks in, the infrasound detector automatically detects the intruder's actions.
When current was passed through the wire, the force of the magnet made the wire swing sideways, out of the mercury, which broke the current to the magnet, so the wire fell back. The modern electric bell mechanism had its origin in vibrating "contact breaker" or interrupter mechanisms devised to break the primary current in induction coils. [5]
A fire alarm box, fire alarm call box, or fire alarm pull box is a device used for notifying a fire department of a fire or a fire alarm activation. Typically installed on street corners or on the outside of commercial buildings in urban areas, they were the main means of summoning firefighters before the general availability of telephones.
A bell character (sometimes bell code) is a device control code originally sent to ring a small electromechanical bell on tickers and other teleprinters and teletypewriters to alert operators at the other end of the line, often of an incoming message.
A ring generator or ringing voltage generator is a device which outputs 20 cycle sinusoidal AC at up to 110 volts peak to power bells or annunciators in one or more telephone extensions. [4] The output stops if a handset is taken off the hook. In terminology devised by phone phreaks, a ringing generator is a magenta box.