Patents by Inventor Daniel Johannes Gerardus Janssen

Daniel Johannes Gerardus Janssen 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).

  • Current stabilizing circuit
    Patent number: 4117391
    Abstract: A current stabilizing circuit comprises a difference amplifier having a defined offset voltage which provides a current which is independent of the operating voltage applied across the circuit. The offset voltage is obtained by using an emitter-coupled pair of transistors with mutually differently current densities as the input stage of the difference amplifier.
    Type: Grant
    Filed: March 10, 1977
    Date of Patent: September 26, 1978
    Assignee: U.S. Philips Corporation
    Inventor: Daniel Johannes Gerardus Janssen
  • Protection device for a subscriber's telephone set
    Patent number: 4079211
    Abstract: A protection circuit for a subscriber's telephone set which comprises a resistor applied in series with the subscriber's line to which resistor a threshold device is connected in parallel, a network being provided which comprises the control input and which is connected between the subscribers' lines while the output of the threshold device is connected to the control input to switch the normally high impedance to a low impedance when the threshold voltage of the threshold device is exceeded by the voltage across the resistor.
    Type: Grant
    Filed: June 18, 1976
    Date of Patent: March 14, 1978
    Assignee: U.S. Philips Corporation
    Inventor: Daniel Johannes Gerardus Janssen
  • Line matching circuit for use in a tone pushbutton dialling subscriber's set provided with a tone generator
    Patent number: 3982078
    Abstract: An impedance matching circuit for a pushbutton telephone uses two voltage regulating transistors having their emitter-collector terminals connected in parallel with a potentiometer, the output terminals of the telephone set, and the output of a pushbutton tone generator amplifier. The base terminal of one of the transistors is connected directly to a tap of the potentiometer, while the base of the second transistor is connected to a further tap on the potentiometer through a low pass filter.
    Type: Grant
    Filed: May 22, 1974
    Date of Patent: September 21, 1976
    Assignee: U.S. Philips Corporation
    Inventors: Daniel Johannes Gerardus Janssen, Cornelis Maria Hart