Patents by Inventor Robert Ahr

Robert Ahr 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).

  • Patent number: 5907292
    Abstract: This circuit arrangement comprises a transformer (2) for transmitting a measurement current (I), which is output by a sensor arrangement (1) at a measurement location situated in an intrinsically safe area (10), to a non-intrinsically safe area (20), in which a current measuring resistor (5) is situated. A DC converter (3) serves for the power supply of the sensor arrangement. A transformer (2) belongs to the DC converter (3), has a primary winding, which faces the non-intrinsically safe area, two identical partial windings (21, 22) connected in series in the same sense, and a single secondary winding (23), which faces the intrinsically safe area. A first end of the current measuring resistor (5) is connected to a circuit zero-point (SN) and a second end to a center tap of an output stage (31) of the DC converter (3). The center tap is connected to the input of an offset adjusting stage (6), an output of which is connected to the input of a voltage/current converter (7).
    Type: Grant
    Filed: June 26, 1997
    Date of Patent: May 25, 1999
    Assignee: Endress + Hauser Wetzer GmbH + Co. KG
    Inventor: Robert Ahr