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Children. Norma and Albert Jr. Marie Van Brittan Brown (October 30, 1922 – February 2, 1999) was an American nurse, her husband Albert L. Brown, an electronics technician. In 1966 they invented an audio-visual home security system [1][2] That same year they applied for a patent for their security system. It was granted three years later in 1969.
The telephone played a major communications role in American history from the 1876 publication of its first patent by Alexander Graham Bell onward. In the 20th century the American Telephone and Telegraph Company (AT&T) dominated the telecommunication market as the at times largest company in the world, until it was broken up and replaced by a ...
30 October 1891: The independent Strowger Automatic Telephone Exchange Company is formed. 3 May 1892: Thomas Edison awarded patents for the carbon microphone based on applications lodged in 1877. 18 October 1892: Opening of telephone service between New York and Chicago (950 miles).
The parent of all mercury pressure gauges is the mercury barometer invented by Evangelista Torricelli in 1643. [15] An early engineering application of the mercury pressure gauge was to measure pressure in steam boilers during the age of steam. The first use on steam engines was by James Watt while developing the Watt steam engine between 1763 ...
A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface troughs, pressure systems and frontal boundaries.
Alexander Graham Bell was awarded the first U.S. patent for the invention of the telephone in 1876. Elisha Gray, 1876, designed a telephone using a water microphone in Highland Park, Illinois. Tivadar Puskás proposed the telephone switchboard exchange in 1876. Thomas Edison invented the carbon microphone which produced a strong telephone ...
Some forecasts project the home security market as a whole will be worth $47 billion by 2020, [12] with the DIY home security market worth $1.5 billion. [13] While the market for home security is expanding, especially with cable TV and Internet service providers introducing their own security and home automation products, it is a fragmented ...
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