1820219

Information

• Patent Grant
• 1820219

• References
• Source

• Patent Number

  1,820,219

• Date Filed

  Not available

• Date Issued

  Tuesday, August 25, 1931
  92 years ago

• CPC

  • G01J5/56 - Electrical features

• US Classifications

  • 356 - Optics: measuring and testing
  • 313 - Electric lamp and discharge devices
  • 315 - Electric lamp and discharge devices: systems