(under subclass 200) Subject matter which includes magnetic field sensing devices, per se, which are not classified elsewhere.
SEE OR SEARCH THIS CLASS, SUBCLASS:
213, for a magnetic recording medium placed on a magnetized test material which assumes the magnetization of the material and requires iron particles to visibly see the pattern of recording medium.
214, for paramagnetic particles placed in a tested magnetic field to note the pattern of the test field or on a magnetized test material to note the magnetization pattern of the magnetized material.
220+, for magnetic field sensing device and a support for the device to hold, position, or move the device in a pipe or borehole.
226, for apparatus involving a magnetic field detector combined with a diverse art device of another class.
228+, for means to create a magnetic test field and a magnetic sensor of the test magnetic field.
244+, for magnetometers which involve a magnetic sensor and an indicator responsive to the sensor. SEE OR SEARCH CLASS
29, Metal Working,
595, for indicating transducer making processes.
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), appropriate subclasses, including
108, 414, and 421-427, for devices responsive to magnetic field.
338, Electrical Resistors,
32+, for magnetic field or compass resistive devices including those of the Hall and superconductive type.
343, Communications: Radio Wave Antennas,
700+, for antennas.
360, Dynamic Magnetic Information Storage or Retrieval,
110+, for magnetic transducers, per se, used in dynamic magnetic information systems. 361, Electricity: Electrical Systems and Devices,
139+, particularly subclasses 170+ for condition responsive control circuits for electromagnetic relay or solenoid devices, including subclasses 179+ for metal presence or absence devices.
365, Static Information Storage and Retrieval, for static magnetic information devices and the storage elements, per se, especially
157, for magnetostrictive; and subclass 160 for superconductive information storage devices.
367, Communication, Electrical: Acoustic Wave Systems and Devices,
156, and 168 for underwater magnetostrictive transducers.
