(under the class definition) Subject matter wherein an element exhibits a permanent external electrostatic field due to internal polarization.
(1) Note. Electrets, per se, are classified here.
SEE OR SEARCH CLASS
29, Metal Working,
886, for the mechanical manufacture of electrets.
106, Compositions: Coating or Plastic, appropriate subclasses for a nonresinous plastic electrically insulating composition in an electrically noncharged state.
260, Chemistry of Carbon Compounds,
2.01, and appropriate classes and subclasses for a resinous plastic electrically-insulating composition in an electrically noncharged state. 365, Static Information Storage and Retrieval,
146, for electrets utilized for storage and retrieval of information.
367, Communications, Electrical: Acoustic Wave Systems and Devices,
170, for electrets used in a acoustic wave system.
374, Thermal Measuring and Testing,
177, for an electrical thermometer having a ferroelectric sensor.
381, Electrical Audio Signal Processing Systems and Devices,
