Patents by Inventor Thomas J. Barzen

Thomas J. Barzen 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).

  • Start-up circuit for negative inductance multiplier
    Patent number: 4467269
    Abstract: A circuit for increasing the inductance of a transformer as used in a telephone line circuit. An operational amplifier with appropriate feedback is connected across a separate winding of the transformer to provide the reactive inductance. To compensate for changes in resistance of the winding, a field effect transistor is controlled by the same amplifier output to provide a positive resistance in the feedback path and thus maintain balance. An operational amplifier and diode are arranged to cooperate with the negative inductor to prevent lock-up.
    Type: Grant
    Filed: October 26, 1982
    Date of Patent: August 21, 1984
    Assignee: GTE Automatic Electric Inc.
    Inventor: Thomas J. Barzen
  • Negative inductance multiplier circuit including temperature compensation
    Patent number: 4463307
    Abstract: A circuit for increasing the inductance of a transformer as used in a telephone line circuit. An operational amplifier with appropriate feedback is connected across a separate winding of the transformer to provide the reactive inductance. To compensate for changes in resistance of the winding, a field effect transistor is controlled by the same amplifier output to provide a positive resistance in the feedback path and thus maintain balance.
    Type: Grant
    Filed: October 26, 1982
    Date of Patent: July 31, 1984
    Assignee: GTE Automatic Electric Inc.
    Inventors: Frederick J. Kiko, Thomas J. Barzen