1686901

Information

• Patent Grant
• 1686901

• References
• Source

• Patent Number

  1,686,901

• Date Filed

  Not available

• Date Issued

  Tuesday, October 9, 1928
  96 years ago

• CPC

  • H04R21/028 - with a fluid as resistance material

• US Classifications

  • 381 - Electrical audio signal processing systems and devices
  • 367 - Communications, electrical: acoustic wave systems and devices