2250781

Information

• Patent Grant
• 2250781

• References
• Source

• Patent Number

  2,250,781

• Date Filed

  Not available

• Date Issued

  Tuesday, July 29, 1941
  83 years ago

• CPC

  • H04R21/023 - with more than one granular chamber
  • H04R21/02 - Microphones
  • H04R21/021 - with granular resistance material

• US Classifications

  • 381 - Electrical audio signal processing systems and devices