1809713

Information

• Patent Grant
• 1809713

• References
• Source

• Patent Number

  1,809,713

• Date Filed

  Not available

• Date Issued

  Tuesday, June 9, 1931
  93 years ago

• CPC

  • H04R21/028 - with a fluid as resistance material

• US Classifications

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