Ernst Alexanderson
Encyclopedia
Ernst Frederick Werner Alexanderson (January 25, 1878 – May 14, 1975) was a Swedish-American electrical engineer, who was a pioneer in radio
and television
development.
in Stockholm
and the Technische Hochschule
(Technical University) in Berlin
, Germany
. He emigrated to the U.S. in 1902 and spent much of his life working for the General Electric
company. He designed the Alexanderson alternator
, a high-frequency generator for longwave transmissions, which made modulated (voice) radio broadcasts practical. The only surviving transmitter in a working state is at the Grimeton radio station outside Varberg
, Sweden
. It is a prime example of pre-electronic radio technology and was added to UNESCO
's World heritage list in 2004.
He had been employed at General Electric
for only a short period of time when GE received an order from Canadian-born professor and researcher Reginald Fessenden
for an alternator with much higher frequency than others in existence at that time. In the summer of 1906 Mr. Alexanderson presented a 50 kHz alternator that was installed in Fessenden's radio station in Brant Rock, Massachusetts. By fall its output had been improved to 500 watts and 75 kHz. On Christmas Eve, 1906, Fessenden broadcast the first radio transmission with music and talk, playing the violin and reading the gospel himself. The transmission was heard as far away as the Caribbean Sea
.
Alexanderson also created the amplidyne
, a direct current amplifier.
Mr. Alexanderson was also instrumental in the development of television. The first television
broadcast in the United States was to his GE Plot
home at 1132 Adams Rd, Schenectady, NY, in 1927. Over his lifetime, Mr. Alexanderson received 345 US patents, the last filed in 1968 at age 89. The inventor and engineer remained active to an advanced age, working as a consultant to GE and RCA
in the 1950s. He died in 1975 and was buried at Vale Cemetery in Schenectady, New York
.
and in 2002 the Consumer Electronics Hall of Fame
.
, filed October, 1913; issued February, 1916 – Ignition system, (RFI suppressor), filed June, 1926; issued August, 1929 – Radio signaling system (directional antenna), filed November 1927, issued September 1930
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
and television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
development.
Background
Alexanderson was born at Uppsala, Sweden, and educated at the Royal Institute of TechnologyRoyal Institute of Technology
The Royal Institute of Technology is a university in Stockholm, Sweden. KTH was founded in 1827 as Sweden's first polytechnic and is one of Scandinavia's largest institutions of higher education in technology. KTH accounts for one-third of Sweden’s technical research and engineering education...
in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
and the Technische Hochschule
Technische Hochschule
Technische Hochschule is what an Institute of Technology used to be called in German-speaking countries, as well as in the Netherlands, before most of them changed their name to Technische Universität or Technische Universiteit in the 1970s and in the...
(Technical University) in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
. He emigrated to the U.S. in 1902 and spent much of his life working for the General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
company. He designed the Alexanderson alternator
Alexanderson alternator
An Alexanderson alternator is a rotating machine invented by Ernst Alexanderson in 1904 for the generation of high frequency alternating current up to 100 kHz, for use as a radio transmitter...
, a high-frequency generator for longwave transmissions, which made modulated (voice) radio broadcasts practical. The only surviving transmitter in a working state is at the Grimeton radio station outside Varberg
Varberg
Varberg is a locality and the seat of Varberg Municipality, Halland County, Sweden with 26,041 inhabitants in 2005.Varberg and all of Halland are well known for their 'typical west coast' sandy beaches. In Varberg the coast changes from wide sandy beaches to rocky terrain that continues north into...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. It is a prime example of pre-electronic radio technology and was added to UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
's World heritage list in 2004.
He had been employed at General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
for only a short period of time when GE received an order from Canadian-born professor and researcher Reginald Fessenden
Reginald Fessenden
Reginald Aubrey Fessenden , a naturalized American citizen born in Canada, was an inventor who performed pioneering experiments in radio, including early—and possibly the first—radio transmissions of voice and music...
for an alternator with much higher frequency than others in existence at that time. In the summer of 1906 Mr. Alexanderson presented a 50 kHz alternator that was installed in Fessenden's radio station in Brant Rock, Massachusetts. By fall its output had been improved to 500 watts and 75 kHz. On Christmas Eve, 1906, Fessenden broadcast the first radio transmission with music and talk, playing the violin and reading the gospel himself. The transmission was heard as far away as the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
.
Alexanderson also created the amplidyne
Amplidyne
An amplidyne is an electromechanical amplifier invented during World War II by Ernst Alexanderson. It is usually an AC motor driving a DC generator with modifications to increase the power gain available...
, a direct current amplifier.
Mr. Alexanderson was also instrumental in the development of television. The first television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
broadcast in the United States was to his GE Plot
General Electric Realty Plot
The General Electric Realty Plot, often referred to locally as the GE Realty Plot or just The Plot, is a residential neighborhood in Schenectady, New York, United States...
home at 1132 Adams Rd, Schenectady, NY, in 1927. Over his lifetime, Mr. Alexanderson received 345 US patents, the last filed in 1968 at age 89. The inventor and engineer remained active to an advanced age, working as a consultant to GE and RCA
RCA
RCA Corporation, founded as the Radio Corporation of America, was an American electronics company in existence from 1919 to 1986. The RCA trademark is currently owned by the French conglomerate Technicolor SA through RCA Trademark Management S.A., a company owned by Technicolor...
in the 1950s. He died in 1975 and was buried at Vale Cemetery in Schenectady, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
.
Legacy
In 1983, he was inducted into the National Inventors Hall of FameNational Inventors Hall of Fame
The National Inventors Hall of Fame is a not-for-profit organization dedicated to recognizing, honoring and encouraging invention and creativity through the administration of its programs. The Hall of Fame honors the men and women responsible for the great technological advances that make human,...
and in 2002 the Consumer Electronics Hall of Fame
Consumer Electronics Hall of Fame
The Consumer Electronics Hall of Fame, founded by the Consumer Electronics Association , honors leaders whose creativity, persistence, determination and personal charisma helped to shape the industry and made the consumer electronics marketplace what it is today...
.
Patents
– High frequency alternator (100 kHz), filed April, 1909; issued, November, 1911 – Selective Tuning System (Tuned RF CircuitTuned radio frequency receiver
A tuned radio frequency receiver is a radio receiver that is usually composed of several tuned radio frequency amplifiers followed by circuits to detect and amplify the audio signal. Prevalent in the early 20th century, it can be difficult to operate because each stage must be individually tuned...
, filed October, 1913; issued February, 1916 – Ignition system, (RFI suppressor), filed June, 1926; issued August, 1929 – Radio signaling system (directional antenna), filed November 1927, issued September 1930
External links
- Consumer Electronics Hall of Fame
- Inventor's Hall of Fame citation accessed April 10, 2006
- Biography at IEEE History Center accessed July 8th, 2011
- Biography at Oldradio.com accessed April 10, 2006
- Illustrated biography at prof. Eugenii Katz website accessed April 10, 2006
- Fessenden and Marconi – their technologies and transatlantic experiments compared. Accessed April 10, 2006
- Transoceanic Radio Communication in 1920, by E.F.W. Alexanderson accessed April 10, 2006
- "A Historical Review of Continuous Wave Radio Frequency Power Generators" accessed April 10, 2006