Telecommunication Telecommunication PioneersPioneers

Day 3Day 3

Benjamin FranklinBenjamin Franklin

1747 Leydn jar 1747 Leydn jar was was the first capacitorthe first capacitor

1752 discovers that 1752 discovers that electricity has a electricity has a positive and a positive and a negative charge negative charge

1752 flew a kite to 1752 flew a kite to demonstrate demonstrate electricity and electricity and lightening relatedlightening related

Luigi Galvani Luigi Galvani

1737-1798, Italian1737-1798, Italian 1780 noticed frog’s 1780 noticed frog’s

leg jumpleg jump effects of effects of

electrostatic stimuli electrostatic stimuli applied to the applied to the muscle fiber of frogs muscle fiber of frogs

““animal electricity”animal electricity” Inspired VoltaInspired Volta

Count Alessandro Count Alessandro Giuseppe Antonio Giuseppe Antonio Anastasio Volta Anastasio Volta

(1745 - 1827) (1745 - 1827) ItalianItalian

1775 created the 1775 created the electrophoruselectrophorus

1800 created the 1800 created the voltaic pilevoltaic pile

Volt named after Volt named after himhim

Hans Christian ØrstedHans Christian Ørsted

1777 - 1851, 1777 - 1851, DanishDanish

1820 a magnetic 1820 a magnetic needle is deflected needle is deflected at right angles to at right angles to a wire carrying an a wire carrying an electric currentelectric current

electromagnetic electromagnetic induction induction

André AmpèreAndré Ampère

(1775-1836), French(1775-1836), French combined theory of combined theory of

magnetism and elec-magnetism and elec-tricity in early 1820'stricity in early 1820's

electrical current electrical current creates magnetic creates magnetic fieldsfields

system to measure system to measure current flow called current flow called amperesamperes

Georg Simon Ohm Georg Simon Ohm

1787-1854, German1787-1854, German describes relation-describes relation-

ship between ship between current flow, current flow, voltage, and voltage, and resistance resistance

Ohm’s LawOhm’s Law Resistance measureResistance measure

Joseph Henry Joseph Henry

(1797-1878), (1797-1878), AmericanAmerican

discovered electro-discovered electro-magnetic induction magnetic induction

discovered self-discovered self-inductanceinductance

Inductance Inductance measure is the measure is the HenryHenry

Michael Faraday Michael Faraday

(1791-1867), British (1791-1867), British foremost foremost

experimental experimental scientist of his day scientist of his day

discovery of electro-discovery of electro-magnetic induction magnetic induction

the induction of one the induction of one electric current by electric current by anotheranother

James Clerk MaxwellJames Clerk Maxwell

(1831-1879), British (1831-1879), British mathematical basis mathematical basis

for electricity and for electricity and electromagnetismelectromagnetism

propagation of propagation of electromagnetic electromagnetic waveswaves

light is made up of light is made up of electromagnetic electromagnetic waves.waves.

Heinrich Rudolph Hertz Heinrich Rudolph Hertz

(1857-94), German(1857-94), German demonstrates the demonstrates the

pro-duction and pro-duction and detection of detection of Maxwell's wavesMaxwell's waves

photoelectric effect photoelectric effect Frequency in HertzFrequency in Hertz

Thomas Alva EdisonThomas Alva Edison

(1847 - 1931), (1847 - 1931), AmericanAmerican

1887 creates the 1887 creates the carbon carbon microphone microphone

Guglielmo MarconiGuglielmo Marconi (1874-1937), Italian(1874-1937), Italian Father of WirelessFather of Wireless 1894 Began work 1894 Began work

following Hertzfollowing Hertz 1895 short range 1895 short range

radioradio 1899 Britain to 1899 Britain to

FranceFrance 1901 Britain to 1901 Britain to

CanadaCanada

Nathan B. Stubblefield Nathan B. Stubblefield

(1860-1928), US(1860-1928), US 1892 invents “wireless telephone”1892 invents “wireless telephone” first person to transmit human first person to transmit human

voice without wiresvoice without wires demonstrates system officially May demonstrates system officially May

30, 1902 in Philadelphia30, 1902 in Philadelphia

Reginald A. FessendenReginald A. Fessenden

(1866-1932), born (1866-1932), born in Canada of US in Canada of US parentsparents

designs a high-designs a high-frequency frequency alternator for alternator for continuos signalcontinuos signal

1906 Christmas Eve 1906 Christmas Eve First broadcast of First broadcast of speech & musicspeech & music

Lee De ForestLee De Forest (1873-1961) US(1873-1961) US 1906 Invents the 1906 Invents the

“audion” now called “audion” now called a triode. Types of a triode. Types of vacuum tube.vacuum tube.

key component in key component in nearly all radio, nearly all radio, radar, TV, and radar, TV, and computers until computers until transistorstransistors