Peder Oluf Pedersen

{{Short description|Danish engineer and physicist}}

{{more citations needed|date=September 2011}}

{{other people|Peter Peterson}}

{{Infobox scientist

| name = Peder Oluf Pedersen

| image = Replace this image male.svg

| caption =

| birth_date = {{Birth date|1874|6|19|df=y}}

| birth_place = Sig, Varde, Denmark

| death_date = {{death date and age|1941|8|30|1874|6|19|df=y}}

| death_place = Copenhagen, Denmark

| nationality = Danish

| field = Physicist

| work_institution = College of Advanced Technology

| alma_mater = College of Advanced Technology

| known_for = Wire recording, the arc converter (both in collaboration with Valdemar Poulsen)

| prizes = Royal Danish Academy of Sciences and Letters Gold Medal (1907)
H. C. Ørsted Medal (1928)
IRE Medal of Honor (1930)

| spouse = {{marriage|Maria Theodora Lihme|1899}}(1871-1930)
Emma Clausen Gad (1902-1997)

| children = Kai Oluf Pedersen (1901-1991) (scientist)
Ellen Margrethe Charlotte Pedersen (1903-1979) married to Børge Jessen (both mathematicians)
Gunnar Pedersen (1905-1997) Director General of The Postal and Telegraph Directorate
Inger Margrethe Pedersen, married name Krøncke (1909-1997) (author)
3 children with his second wife

}}

Peder Oluf Pedersen (19 June 1874 – 30 August 1941) was a Danish engineer and physicist. He is notable for his work on electrotechnology, his cooperation with Valdemar Poulsen on the developmental work on Wire recorders, which he called a telegraphone, the arc converter known as the Poulsen Arc Transmitter, and his work on electrical currents in the ionosphere.

File:Valdemar Poulsen and P.O. Pedersen by Knud Larsen.png, 1915.]]

Pedersen became a professor of telegraphy, telephony and radio in 1912.[http://www.ieeeghn.org/wiki/index.php/Peder_Pedersen Biography] from the IEEE History Center retrieved 2011 Sept 28

He became principal of the College of Advanced Technology (Den Polytekniske Læreanstalt) in 1922, a title he held until his death. He was a Fellow of the American Institute of Electrical Engineers and was a member of the British Institution of Electrical Engineers. In 1915 he became a Fellow of the Institute of Radio Engineers.

The first expression for the Pedersen current was formulated by Pedersen from in his 1927 work "The Propagation of Radio Waves along the Surface of the Earth and in the Atmosphere",{{cite journal |last1=Pedersen |first1=Peder Oluf |title=The Propagation of Radio Waves along the Surface of the Earth and in the Atmosphere |journal=Danmarks naturvidenskabelige Samfund |date=1927 |volume=A |issue=15a}}{{cite web |title=Peder Oluf Pedersen |url=http://tekhist.pastperfectonline.com/person/E3FDBDA0-E5FB-4DD9-BD13-621050435859 |website=dtu.dk |publisher=DTU |access-date=16 July 2023}}{{cite web |title=Person Record |url=http://tekhist.pastperfectonline.com/person/E3FDBDA0-E5FB-4DD9-BD13-621050435859 |website=tekhist.pastperfectonline |publisher=DTU Historie |access-date=16 July 2023}} where he pointed out that the geomagnetic field means that the conductivity of the ionosphere is anisotropic.{{Cite journal| doi = 10.1007/BF02746310| issn = 1827-6121| volume = 4| issue = 4| pages = 1385–1412| last = Chapman| first = S.| title = The electrical conductivity of the ionosphere: A review| journal = Il Nuovo Cimento (1955-1965)| accessdate = 2023-07-16| date = 1956-08-01| url = https://doi.org/10.1007/BF02746310| url-access = subscription}}