TREA

with more than one granular chamber

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Industry

  • CPC
  • H04R21/023
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Parent Industries

HELECTRICITY H04Electric communication H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS DEAF-AID SETS PUBLIC ADDRESS SYSTEMS H04R21/00Variable-resistance transducers

Current Industry

H04R21/023with more than one granular chamber
Industries

Patents Grantslast 30 patents

  • Information Patent Grant

    2610252
    • Patent number 2,610,252
    • Issue date Sep 9, 1952
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2250781
    • Patent number 2,250,781
    • Issue date Jul 29, 1941
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2179733
    • Patent number 2,179,733
    • Issue date Nov 14, 1939
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    2136345
    • Patent number 2,136,345
    • Issue date Nov 8, 1938
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1976692
    • Patent number 1,976,692
    • Issue date Oct 9, 1934
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1944720
    • Patent number 1,944,720
    • Issue date Jan 23, 1934
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1901933
    • Patent number 1,901,933
    • Issue date Mar 21, 1933
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1768211
    • Patent number 1,768,211
    • Issue date Jun 24, 1930
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1765449
    • Patent number 1,765,449
    • Issue date Jun 24, 1930
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1704098
    • Patent number 1,704,098
    • Issue date Mar 5, 1929
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1695875
    • Patent number 1,695,875
    • Issue date Dec 18, 1928
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1661006
    • Patent number 1,661,006
    • Issue date Feb 28, 1928
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1656425
    • Patent number 1,656,425
    • Issue date Jan 17, 1928
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1647244
    • Patent number 1,647,244
    • Issue date Nov 1, 1927
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1628898
    • Patent number 1,628,898
    • Issue date May 17, 1927
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1624353
    • Patent number 1,624,353
    • Issue date Apr 12, 1927
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1624352
    • Patent number 1,624,352
    • Issue date Apr 12, 1927
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1603300
    • Patent number 1,603,300
    • Issue date Oct 19, 1926
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1509818
    • Patent number 1,509,818
    • Issue date Sep 23, 1924
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1496919
    • Patent number 1,496,919
    • Issue date Jun 10, 1924
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1446544
    • Patent number 1,446,544
    • Issue date Feb 27, 1923
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1335592
    • Patent number 1,335,592
    • Issue date Mar 30, 1920
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1175048
    • Patent number 1,175,048
    • Issue date Mar 14, 1916
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1156867
    • Patent number 1,156,867
    • Issue date Oct 12, 1915
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1144391
    • Patent number 1,144,391
    • Issue date Jun 29, 1915
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1090557
    • Patent number 1,090,557
    • Issue date Mar 17, 1914
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1077373
    • Patent number 1,077,373
    • Issue date Nov 4, 1913
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1073667
    • Patent number 1,073,667
    • Issue date Sep 23, 1913
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1049253
    • Patent number 1,049,253
    • Issue date Dec 31, 1912
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE
  • Information Patent Grant

    1048253
    • Patent number 1,048,253
    • Issue date Dec 24, 1912
    • H04 - ELECTRIC COMMUNICATION TECHNIQUE