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This is an accepted version of this page This is the latest accepted revision, reviewed on 17 November 2024. Type of clock A traditional wind-up (key-wound), mechanical spring-powered alarm clock An alarm clock or alarm is a clock that is designed to alert an individual or group of people at a specified time. The primary function of these clocks is to awaken people from their night's sleep or ...
The word alarm comes from the Old French a l'arme meaning "to the arms", or "to the weapons", telling armed men to pick up their weapons and get ready for action because an enemy may have suddenly appeared. [1] The word alarum is an archaic form of alarm. It was sometimes used as a call to arms in the stage directions of Elizabethan dramas. [2]
The uniqueness of the clock was its capability to announce dual-times automatically with visual and audible signals. [47] Jang developed a signal conversion technique that made it possible to measure analog time and announce digital time simultaneously as well as to separate the water mechanisms from the ball-operated striking mechanisms. [ 48 ]
AP World History: Modern was designed to help students develop a greater understanding of the evolution of global processes and contacts as well as interactions between different human societies. The course advances understanding through a combination of selective factual knowledge and appropriate analytical skills.
Residential smoke alarms are usually powered with a 9-volt battery, or by mains electricity. Some smoke alarms use a combination of the 2; usually using the 9V battery as an extra power source in the event of an outage. Commercial smoke detectors issue a signal to a fire alarm control panel as part of a fire alarm system. Usually, an individual ...
A fire alarm notification appliance is an active fire protection component of a fire alarm system. A notification appliance may use audible, visible, or other stimuli to alert the occupants of a fire or other emergency condition requiring action. Audible appliances have been in use longer than any other method of notification.
The invention of the verge and foliot escapement in c.1275 [87] was one of the most important inventions in both the history of the clock [88] and the history of technology. [89] It was the first type of regulator in horology. [6] A verge, or vertical shaft, is forced to rotate by a weight-driven crown wheel, but is stopped from rotating freely ...
Morse code can be transmitted in a number of ways: Originally as electrical pulses along a telegraph wire, but later extended to an audio tone, a radio signal with short and long tones, or high and low tones, or as a mechanical, audible, or visual signal (e.g. a flashing light) using devices like an Aldis lamp or a heliograph, a common ...