In a matter of decades after their creation in edward hughes electrical and electronic technology pdf 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans almost instantly, with widespread social and economic impacts. Unsourced material may be challenged and removed.
Telegraphs employing electrostatic attraction were the basis of early experiments in electrical telegraphy in Europe, but were abandoned as being impractical and were never developed into a useful communication system. The telegraph receiver’s operator would watch the bubbles and could then record the transmitted message. 1820 that an electric current produces a magnetic field which will deflect a compass needle. 1828 by placing several windings of insulated wire around the bar, creating a much more powerful electromagnet which could operate a telegraph through the high resistance of long telegraph wires. 1826 to 1832, Henry first demonstrated the theory of the ‘magnetic telegraph’ by ringing a bell through a mile of wire strung around the room.
Davy’s relay used a magnetic needle which dipped into a mercury contact when an electric current passed through the surrounding coil. This allowed a weak current to switch a larger current to operate a powerful local electromagnet over very long distances. 1837 and was granted a patent on 4 July 1838. He also developed an electric relay. 1816 and used static electricity. 175 yard long trench as well as an eight mile long overhead telegraph.
The lines were connected at both ends to revolving dials marked with the letters of the alphabet and electrical impulses sent along the wire were used to transmit messages. Elements of Ronalds’ design were utilised in the subsequent commercialisation of the telegraph over 20 years later. Canstatt in 1832 had a transmitting device which consisted of a keyboard with 16 black-and-white keys. These served for switching the electric current. When at the starting station the operator pressed a key, the corresponding pointer was deflected at the receiving station. Different positions of black and white flags on different disks gave combinations which corresponded to the letters or numbers.
Pavel Schilling subsequently improved its apparatus. He reduced the number of connecting wires from eight to two. On 21 October 1832, Schilling managed a short-distance transmission of signals between two telegraphs in different rooms of his apartment. However, the project was cancelled following Schilling’s death in 1837.
As a result, he was able to make the distant needle move in the direction set by the commutator on the other end of the line. The alphabet was encoded in a binary code which was transmitted by positive or negative voltage pulses which were generated by means of moving an induction coil up and down over a permanent magnet and connecting the coil with the transmission wires by means of the commutator. Gauss was convinced that this communication would be a help to his kingdom’s towns. He installed a telegraph line along the first German railroad in 1835.
In 1836, an American scientist, Dr. American electric telegraph, in Elderton, Pennsylvania, one year before the Morse telegraph. Alter demonstrated it to witnesses but never developed the idea into a practical system. When Alter was interviewed for the book Biographical and Historical Cyclopedia of Indiana and Armstrong Counties, he said: “I may say that there is no connection at all between the telegraph of Morse and others and that of myself. Professor Morse most probably never heard of me or my Elderton telegraph. It embossed dots and dashes on a moving paper tape by a stylus which was operated by an electromagnet. In May 1837 they patented a telegraph system which used a number of needles on a board that could be moved to point to letters of the alphabet.