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The Dawn of the Electric Age: From Pre-electronic Communication to Telegraphy

Explore the fascinating evolution of communication, from ancient pictographs to the development of the alphabet, printing, and the transfer of information. Learn about the pioneers of the electric age, including Samuel Morse and his telegraphy code, and discover how electricity has shaped our modern world.

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The Dawn of the Electric Age: From Pre-electronic Communication to Telegraphy

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  1. Chaos, Communication and ConsciousnessModule PH19510 Lecture 4 The Dawn of the Electric Age

  2. Review of Lecture #2 • Pre-electronic Communication • Pictographs • Development of the alphabet • Number systems • Printing • Transfer of Information • Navigation • Signalling

  3. CommunicationThe dawn of the electric age • The Electric Pioneers • First messages by wire • Development of telegraphy • Samuel Morse and his code

  4. Highly RecommendedElectric Universe • David Bodanis • £7.99 • ISBN • 0-349-11766-7 • Aventis prize for popular science • How Electrons hold the universe together

  5. Electricity in antiquity • Lightning • Ancient Greece • Thales (600BC) • Rubbed Amber with fur  picked up feathers • Static electricity • “Resinous” vs “Vitreous”

  6. Benjamin Franklin (1706-1790) • Printer, scientist, writer, inventor, activist, statesman • Static electricity • +ve and –ve charge • 1752 Proved storm clouds are charged

  7. Luigi Galvani (1737-1798) • 1780 Frogs leg • Dissimilar metals • Static • Bioelectricity

  8. Alessandro Volta (1745-1827) • Lombary, Italy • 1800 • Voltaic pile • Battery • Zinc/Silver • Brine/Cardboard • Steady current

  9. +ve The Zinc/Silver Cell • Zinc Anode • Silver Cathode • Zn(s)  Zn2+(aq) + 2e- • 2H+(aq)+2e-  H2 (g) • ≈0.75 volts/element Ag Cardboard + Brine -ve Zn

  10. 1820 – A key year • Link between Electricity & Magnetism • HC Ørsted (Denmark) • Compass needle • Galvanometer • J Schweigger • Wind wire around compass • Increased sensitivity

  11. Andrè-Marie Ampere (1775-1836) • 1820 Formalised EM Theory • 1821 Proposed Telegraphy with galvanometers • 1 wire per galvanometer • 200 ft (60-70m)

  12. Early systems based on galvanometers • Schilling 1832 • Gauss & Weber 1833 • Wheatstone & Cooke • 5 Needle Telegraph 1837 • Commercial system 1839

  13. William Sturgeon invents the Electromagnet 1825 • b. 1783 • 1825 Electromagnet • Coil of wire on iron • Uninsulated wire

  14. Joseph Henry (1797-1878) – Electrical signalling at a distance • 1827 Improves electromagnet • Many turns of insulated wire • 1830 First signalling • Ring bell >1 mile of cable • 1837 Electromechanical Relay

  15. The electromechanical relay • Switch held open by spring • Electromagnet • Current flows in electromagnet •  magnetic field •  switch actuated • Current flows in switched circuit

  16. Samuel Morse & Alfred Vail • 1838 – First system test • Vail developed signalling code • 1843 – U.S. congress funds $30,000 for line from Washington to Baltimore – 40 miles (65km) • 1844 Line operational • “What hath God wrought”

  17. Morse’s apparatus • Paper tape moved by clockwork • Electromagnet pulls ‘pendulum’ • Marks embossed on paper tape

  18. Paper Tape Output

  19. Morse Code • Evolved from Vail’s original • Letters & Numbers • Punctuation • 2 symbols • Dot • Dash • Variable length • Frequent letters, shortest codes

  20. Review of Lecture #3 • Dawn of the electric age • Key technologies • Cells & Batteries • Electromagnet • Relay • Use of standardised code

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