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Earth-return telegraph is the system whereby the return path for the electric current of a telegraph circuit is provided by connection to the earth through an earth electrode. Using earth return saves a great deal of money on installation costs since it halves the amount of wire that is required, with a corresponding saving on the labour ...
Cooke and Wheatstone's five-needle telegraph from 1837 Morse telegraph Hughes telegraph, an early (1855) teleprinter built by Siemens and Halske. Electrical telegraphy is a point-to-point text messaging system, primarily used from the 1840s until the late 20th century.
The word telegraph (from Ancient Greek: τῆλε 'at a distance' and γράφειν 'to write') was coined by the French inventor of the semaphore telegraph, Claude Chappe, who also coined the word semaphore. [2] A telegraph is a device for transmitting and receiving messages over long distances, i.e., for telegraphy.
The circuit shown in the bottom diagram only can model the differential mode. In the top circuit, the voltage doublers, the difference amplifiers, and impedances Z o (s) account for the interaction of the transmission line with the external circuit. This circuit is a useful equivalent for an unbalanced transmission line like a coaxial cable.
The Cooke and Wheatstone telegraph was an early electrical telegraph system dating from the 1830s invented by English inventor William Fothergill Cooke and English scientist Charles Wheatstone. It was a form of needle telegraph, and the first telegraph system to be put into commercial service. The receiver consisted of a number of needles that ...
The ground was used as the return path for current in the telegraph circuit, to avoid having to use a second overhead wire. [ 24 ] By the 1860s, the telegraph was the standard way to send most urgent commercial, diplomatic and military messages, and industrial nations had built continent-wide telegraph networks, with submarine telegraph cables ...
A telegraph operator at the sending end of the line would create the message by tapping on a switch called a telegraph key, which rapidly connects and breaks the circuit to a battery, sending pulses of current down the line. The telegraph sounder was used at the receiving end of the line to make the Morse code message audible.
An optical telegraph is a line of stations, ... Diagram of UK Murray six-shutter system, with shutter 6 in the horizontal position, and shutters 1–5 vertical.