1689121

Information

• Patent Grant
• 1689121

• References
• Source

• Patent Number

  1,689,121

• Date Filed

  Not available

• Date Issued

  Tuesday, October 23, 1928
  96 years ago

• CPC

  • H03H9/46 - Filters
  • Y10S200/20 - Sound and vibration operated

• US Classifications

  • 367 - Communications, electrical: acoustic wave systems and devices
  • 178 - Telegraphy
  • 200 - Electricity: circuit makers and breakers
  • 330 - Amplifiers