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[[da:Valdemar Poulsen]]
[[de:Valdemar Poulsen]]
[[esen:Valdemar Poulsen]]
[[fr:Valdemar Poulsen]]
[[it:Valdemar Poulsen]]
[[nl:Valdemar Poulsen]]
[[ja:ヴォルデマール・ポールセン]]
[[pl:Valdemar Poulsen]]
[[ru:Поульсен, Вальдемар]]
[[sv:Valdemar Poulsen]]
[[tr:Valdemar Poulsen]]
[[uk:Поульсен Вальдемар]]
{{Infobox engineer
|image =Valdemar-poulsen-c1898.jpg
|image_width = 150px
|caption = {{Infobox engineer
|image =Valdemar-poulsen-c1898.jpg
|image_width = 150px
|caption = Valdemar Poulsen (c. 1898)
|name = Valdemar Poulsen
|nationality = [[Denmark|Danish]]
|birth_date = 23 November 1869
|birth_place = [[Copenhagen]]
|death_date = 23 July 1942
|death_place =
|education =
|spouse =
|parents =
|children =
|discipline =
|institutions =
|practice_name =
|significant_projects = [[Wire recording|magnetic wire recorder]]
|significant_design =
|significant_advance =
|significant_awards =
}}
[[Image:Telegrafon 8154.jpg|thumb|200px|Poulsen's magnetic wire recorder.]]
'''Valdemar Poulsen''' (23 November 1869 – 23 July 1942) was a [[Denmark|Danish]] [[engineer]] who developed a [[Wire recording|magnetic wire recorder]] in 1899.
==Biography==
He was born on 23 November 1869 in [[Copenhagen]]
The [[magnetic recording]] was demonstrated in principle as early as 1898 by Valdemar Poulsen in his [[telegraphone]]. Magnetic wire recording, and its successor, [[magnetic tape recording]], involve the use of a magnetizable medium which moves past a recording head. An [[electrical signal]], which is analogous to the [[sound]] that is to be recorded, is fed to the [[recording head]], inducing a pattern of magnetization similar to the signal. A [[playback head]] (which may be the same as the recording head) can then pick up the changes in the magnetic field from the tape and convert them into an electrical signal.
[[Image:US Patent 661,619 - Magnetic recorder.jpg|thumb|left|111px|Poulsen's US patent for a magnetic wire recorder.]]
Poulsen obtained a Telegraphone Patent in 1898, and with his assistant, [[Peder Oluf Pedersen|Peder O. Pedersen]], later developed other magnetic recorders that recorded on steel wire, tape, or disks. None of these devices had electronic amplification, but the recorded signal was easily strong enough to be heard through a headset or even transmitted on telephone wires. At the [[1900 World's Fair]] in [[Paris]], Poulsen had the chance to record the voice of Emperor [[Franz Josef of Austria]] which happens to be the oldest surviving magnetic audio recording today.{{Citation needed|date=June 2011}}
Poulsen developed an [[arc converter]] in 1908, referred to as the "Poulsen Arc Transmitter", which was widely used in radio before the advent of [[vacuum tube]] technology.
He died on 23 July 1942.
==Legacy==
A stamp was issued in honor of Poulsen in 1969.
==See also==
* [[Timeline of historic inventions]]
* [[Sound recording]]
* [[List of people on stamps of Denmark]]
==External links==
* "''[http://www.amps.net/newsletters/issue27/27_poulsen.htm 1898 – 1998 Poulsen's patent]''". 100 years of magnetic recording.
* Katz, Eugenii, "''[http://web.archive.org/web/20091027123228/http://geocities.com/neveyaakov/electro_science/poulsen.html Valdemar Poulsen]''". Biosensors & Bioelectronics.
* Poulsen, Valdemar, "''{{US patent|661619|US PAT No. 661,619}} Method of Recordings and Reproducing Sounds or Signals''". Magnetic Tape Recorder.
* [http://web.archive.org/web/20070108004501/http://history.sandiego.edu/gen/recording/qt/franz.mov 1900 World Exposition recording of Emperor Franz Joseph of Austria] by means of Poulsen's telegraphone.
{{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| NAME = Poulsen, Valdemar
| ALTERNATIVE NAMES =
| SHORT DESCRIPTION =
| DATE OF BIRTH = 23 November 1869
| PLACE OF BIRTH = [[Copenhagen]]
| DATE OF DEATH = 23 July 1942
| PLACE OF DEATH =
}}
{{DEFAULTSORT:Poulsen, Valdemar}}
[[Category:People from Copenhagen]]
[[Category:Danish engineers]]
[[Category:Danish inventors]]
[[Category:National Inventors Hall of Fame inductees]]
[[Category:1869 births]]
[[Category:1942 deaths]]
[[bn:ভালদেমার পাউলসেন]]
[[da:Valdemar Poulsen]]
[[de:Valdemar Poulsen]]
[[es:Valdemar Poulsen]]
[[fr:Valdemar Poulsen]]
[[it:Valdemar Poulsen]]
[[nl:Valdemar Poulsen]]
[[ja:ヴォルデマール・ポールセン]]
[[pl:Valdemar Poulsen]]
[[ru:Поульсен, Вальдемар]]
[[sv:Valdemar Poulsen]]
[[tr:Valdemar Poulsen]]
[[uk:Поульсен Вальдемар]]
(~1898)<br/>Valdemar Poulsen (c. 1898)
|name = Valdemar Poulsen
|nationality = [[Denmark|Danish]]
|birth_date = 23 November 1869
|birth_place = [[Copenhagen]]
|death_date = 23 July 1942
|death_place =
|education =
|spouse =
|parents =
|children =
|discipline =
|institutions =
|practice_name =
|significant_projects = [[Wire recording|magnetic wire recorder]]
|significant_design =
|significant_advance =
|significant_awards =
}}
[[Image:Telegrafon 8154.jpg|thumb|200px|Poulsen's magnetic wire recorder.]]
'''Valdemar Poulsen''' (23 November 1869 – 23 July 1942) was a [[Denmark|Danish]] [[engineer]] who developed a [[Wire recording|magnetic wire recorder]] in 1899.
==Biography==
He was born on 23 November 1869 in [[Copenhagen]]
The [[magnetic recording]] was demonstrated in principle as early as 1898 by Valdemar Poulsen in his [[telegraphone]]. Magnetic wire recording, and its successor, [[magnetic tape recording]], involve the use of a magnetizable medium which moves past a recording head. An [[electrical signal]], which is analogous to the [[sound]] that is to be recorded, is fed to the [[recording head]], inducing a pattern of magnetization similar to the signal. A [[playback head]] (which may be the same as the recording head) can then pick up the changes in the magnetic field from the tape and convert them into an electrical signal.
[[Image:US Patent 661,619 - Magnetic recorder.jpg|thumb|left|111px|Poulsen's US patent for a magnetic wire recorder.]]
Poulsen obtained a Telegraphone Patent in 1898, and with his assistant, [[Peder Oluf Pedersen|Peder O. Pedersen]], later developed other magnetic recorders that recorded on steel wire, tape, or disks. None of these devices had electronic amplification, but the recorded signal was easily strong enough to be heard through a headset or even transmitted on telephone wires. At the [[1900 World's Fair]] in [[Paris]], Poulsen had the chance to record the voice of Emperor [[Franz Josef of Austria]] which happens to be the oldest surviving magnetic audio recording today.{{Citation needed|date=June 2011}}
Poulsen developed an [[arc converter]] in 1908, referred to as the "Poulsen Arc Transmitter", which was widely used in radio before the advent of [[vacuum tube]] technology.
He died on 23 July 1942.
==Legacy==
A stamp was issued in honor of Poulsen in 1969.
==See also==
* [[Timeline of historic inventions]]
* [[Sound recording]]
* [[List of people on stamps of Denmark]]
==External links==
* "''[http://www.amps.net/newsletters/issue27/27_poulsen.htm 1898 – 1998 Poulsen's patent]''". 100 years of magnetic recording.
* Katz, Eugenii, "''[http://web.archive.org/web/20091027123228/http://geocities.com/neveyaakov/electro_science/poulsen.html Valdemar Poulsen]''". Biosensors & Bioelectronics.
* Poulsen, Valdemar, "''{{US patent|661619|US PAT No. 661,619}} Method of Recordings and Reproducing Sounds or Signals''". Magnetic Tape Recorder.
* [http://web.archive.org/web/20070108004501/http://history.sandiego.edu/gen/recording/qt/franz.mov 1900 World Exposition recording of Emperor Franz Joseph of Austria] by means of Poulsen's telegraphone.
{{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| NAME = Poulsen, Valdemar
| ALTERNATIVE NAMES =
| SHORT DESCRIPTION =
| DATE OF BIRTH = 23 November 1869
| PLACE OF BIRTH = [[Copenhagen]]
| DATE OF DEATH = 23 July 1942
| PLACE OF DEATH =
}}
{{DEFAULTSORT:Poulsen, Valdemar}}
[[Category:People from Copenhagen]]
[[Category:Danish engineers]]
[[Category:Danish inventors]]
[[Category:National Inventors Hall of Fame inductees]]
[[Category:1869 births]]
[[Category:1942 deaths]]
[[bn:ভালদেমার পাউলসেন]]
[[da:Valdemar Poulsen]]
[[de:Valdemar Poulsen]]
[[es:Valdemar Poulsen]]
[[fr:Valdemar Poulsen]]
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