ECE 1304 Introduction to Electrical and Computer Engineering What is Electrical Engineering? Part 2 (1900 to 1920)

Electromagnetism is a property of the universe that may be used to … What is Electricity? Electromagnetism is a property of the universe that may be used to … Transmit and convert energy. Transmit and manipulate information. Electrical Engineers use these properties to make useful things. 2

Life in 1900 For most, light was provided by kerosene lamps. Those in cities may have gas lighting. The first commercial power system (DC) was implemented in 1882. The mechanical phonograph was invented in 1877 . Motion pictures were a novelty, exhibited to one person at a time. Telephone communication was low-quality, unreliable and local. Telegraph provided long-distance, “high-speed” communication.

Thomas Alva Edison (1847-1931)

Thomas Alva Edison (1847-1931) 1866 Worked for Western Union as a telegraph operator. Edison holds 1093 US patents. 1869 Patented an electrographic vote recorder for the US congress. (They were not interested.) 1869-1876 Awarded numerous patents for telegraphic devices and systems. 1876-1879 Awarded numerous patents for telephonic devices. 1878 Patented the phonograph or speaking machine.

Thomas Alva Edison (1847-1931) 1880 Patented the incandescent light bulb. 1880 Founded the Edison Illuminating Company. 1882 The Pearl Street Generating Station provided 110 volt DC power to 59 customers in lower Manhattan. 1880-1897 Awarded numerous patents for electrical power generation and distribution devices and systems. 1892 Formed the General Electric Company. 1897 Patented the Kinetographic Camera (motion pictures).

Thomas Edison with his phonograph.

Kinetoscope

Nikola Tesla (1856-1943) Ethnical Serb, Born in Croatia. Emigrated to US in 1884 to work for Thomas Edison. Developed alternating current power systems. Patent awarded for the induction motor in 1888.

George Westinghouse (1846-1914) Invented the railway air brake. Developed electrical power distribution based on alternating current.

War of the Currents 1882 Edison started DC Power distribution. 1886 Westinghouse started AC Power distribution. 1888 Media furor over a series of deaths caused by high-voltage AC lines. 1888 Edison’s representatives made claims that AC was hazardous, they proved it by the public electrocution of dogs. They made sure the first electric chair was powered by AC. AC proved to be more economical (Transmission lines are less expensive than generation plants. Large generation plants are more economical than small ones.).

1900 – 1910 1901 – Marconi transmits wireless telegraph signal a distance of 2000 miles. 1903 – Charles Curtis develops the steam turbine generator. 1904 – Sir John Ambrose Fleming invents the vacuum tube and diode. 1906 – Lee De Forest develops the triode vacuum tube. 1908 – First U.S. patent for vacuum cleaner awarded to James Spangler.

Guglielmo Marconi (1874-1937) 1895 Wireless transmission of telegraph signals approximately 1.5 miles. 1897 Founded The Wireless Telegraph & Signal Company. 1901 Transmitted the first wireless signal across the Atlantic Ocean. Two employees of the Marconi Co. were on the RMS Titanic on April 15, 1912.

Lee de Forest (1873-1961) Self described “Father of Radio.” Invented the three-element “Grid Audion” in 1906. It was the foundation of vacuum tube technology. It is not clear that he understood how it worked.

Early Vacuum Tubes

1910 – 1920 1912 – Edwin Howard Armstrong devises one of the first effective amplitude modulation (AM) radio receivers. 1913 – First refrigerator for home use introduced. 1915 – Vacuum tube amplifiers first used in coast-to-coast telephone circuits. 1919 – Charles Strite invents the pop-up toaster.

Edwin Howard Armstrong (1890-1954) 1914 Invented the “regenerative circuit” while an undergraduate. 1918 Invented the superheterodyne receiver. 1933 Invented FM radio.