توضیحNorton mechanical filter.png	English: A mechanical filter designed using electrical network theory
تاریخ	31st May 1929 (filed)
منبع	US patent US1792655
پدیدآور	Edward Lawry Norton
دیگر نسخه‌ها

The text and illustrations of US patents published before March 1, 1989 are in the public domain unless the patent text contains a specific notice that portions are copyrighted. See 37 CFR 1.71(d), 37 CFR 1.84(s) The original patent contains no such notice, so its contents are in the public domain. Note: This only applies to images published before March 1, 1989. Patents published after that date are most likely copyrighted, unless in the public domain for another reason, such as {{PD-ineligible}}.

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• 2009-06-25 22:30 Spinningspark 715×498× (35668 bytes) {{Information |Description=A mechanical filter designed using electrical network theory |Source=US patent US1792655 |Date=31st May 1929 (filed) |Author=[[Edward Lawry Norton]] |other_versions= }} == Licensing == {{PD-US-patent}} {{KeepLocal}}