Beginnings

1
Beginnings
2
600 BC
1780 1800 Galvanic cell
Voltaic pile
1785 Coulombs Law
1745
900 BC
1831 - Henry
1820 - Oersted electromagnetism 1827 Ohms Law
1838 Faradays electromagnetic induction
3
1844 Morse telegraph
1876 Bells telephone
1888 Teslas AC motor
N Tesla
1888 H. Hertz produces electromagnetic waves
1861 Maxwells equations for electromagnetic
fields
1879 Edison electric lamp
4
1906 - de Forest Audion, the first vacuum tube
amplifier
1901 Marconi wirelessly signals across the
Atlantic
1920s onward Radio popularized
1929 Zworykin invents television
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• That was remarkable progress!
• But what was known about the
• physical basis for electricity and conduction?
• What did we really know about the atom?
• not much, until the end of the 19th century, and
  the first quarter of the twentieth.

6
Evolution of Atomic Model
Thomsons raisin pudding model 1897 Planck
energy quanta -1900 Einstein photoelectric
effect - 1905
Rutherfords model 1911
de Broglie wave nature of electron
1924 Paulis exclusion principle
1924 Schrodinger wave mechanics and probability
distribution of electron - 1926
Bohrs model stable orbits -1912
7
Hydrogen Atom Orbitals
8
Conduction of Electricity in Solid Materials
Conductivity is determined by the energy band
structure of the material