Patents by Inventor Eric J. Lundgard

Eric J. Lundgard has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Vacuum tube based audio amplifier
    Patent number: D813189
    Type: Grant
    Filed: August 10, 2017
    Date of Patent: March 20, 2018
    Inventor: Eric J. Lundgard
  • Audio amplifier
    Patent number: D871364
    Type: Grant
    Filed: July 12, 2019
    Date of Patent: December 31, 2019
    Inventor: Eric J. Lundgard