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Expired European patentEurope

Low-pass filtering circuit and method of using the same

EP 0029239 B1 · Applicant: HYDRO-QUEBEC

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Overview

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Filed November 17, 1980 and granted February 26, 1986. A European patent lasts at most 20 years from filing, so its term ended November 17, 2000.
  • A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by May 17, 2006.
  • We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.
FiledNovember 17, 1980
PublishedMay 27, 1981
GrantedFebruary 26, 1986
Term endedNovember 17, 2000
Application numberEP 80107097
Classification (CPC)H03H17/00

Timeline

Timeline From EPO dates

1981198319851987198919911993199519971999Application filedNov 17, 1980PublishedMay 27, 1981Patent grantedFeb 26, 1986Term endedNov 17, 2000

Sources & verification