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Physikalisch-Technische Bundesanstalt


Physikalisch-Technische Bundesanstalt

PTB main entrance in Braunschweig
Atomic clock CS2

The German National Metrology Institute (German: Physikalisch-Technische Bundesanstalt, or PTB) is based in Braunschweig (Brunswick) and Berlin. It is the national institute for natural and engineering sciences and the highest technical authority for metrology and physical safety engineering in Germany.

The PTB is entrusted by the Time Act to realise and disseminate legal time to the public. The most popular means is the transmission of standard frequency and time signals by the longwave time signal DCF77.[1] It is responsible for four German caesium atomic clocks, CS1, CS2, CSF1 and CSF2 . These atomic clocks have an important role in maintaining accurate worldwide time of day as they provide the German UTC(PTB) legal time standard which - combined with other official atomic time standards - is used by the Bureau International des Poids et Mesures to create a single, official Coordinated Universal Time (UTC).[2] In addition, the PTB operates the "stratum 1", and public Network Time Protocol time servers for the distribution of time on the internet.


  • History 1
  • See also 2
  • Bibliography 3
  • External links 4
  • Notes 5


The PTB was originally founded in 1887 as the Physikalisch-Technische Reichsanstalt (PTR) (the Physical and Technical Institute of the calibration and establishing metrological standards. Research areas included spectroscopy, photometry, electrical engineering, and cryogenics. Werner von Siemens was instrumental in its establishment. Until 1934 the PTR was part of the Reichsinnenministerium (the Reich's Ministry of Interior Affairs). After 1934 it became part of the Reichserziehungsministerium (the Reich's Ministry of Education).[3]

The Institute’s board of directors included Heinrich Konen and Walther Nernst around 1930, Albert Einstein (1917–1933), Ludwig Prandtl, and Max Planck, as well as representatives from Siemens AG, Krupp, and Zeiss. Its presidents were:

Max von Laue was the Physics advisor from 1925 to December 1933.[4]

In 1932 the institute had 292 employees; 443 in 1937; over 500 around 1942; about 1500 in 2002 and 1744 in 2008. After the end of World War II in 1945 it was renamed to the Physikalisch-Technische Bundesanstalt (the Federal Institute of Physical and Technical Affairs)[5] and serves as the national metrology institute.[6]

See also


  • Klaus Hentschel, editor and Ann M. Hentschel, editorial assistant and Translator Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996)

External links

  • Physikalisch-Technische Bundesanstalt


  1. ^ "Realisation of Legal Time in Germany". Physikalisch-Technische Bundesanstalt (PTB). 2013-08-08. Retrieved 2013-09-26. 
  2. ^ Definition of Coordinated Universal Time in German law–ZeitG §1 - §5
  3. ^ Hentschel (1996) Appendix B, pp. iv – vii.
  4. ^ Hentschel (1996) Appendix B, pp. iv – vii.
  5. ^ Hentschel (1996) Appendix B, pp. iv – vii.
  6. ^

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