US PATENT SUBCLASS 331 / 158
.~ Crystal

Current as of: June, 1999
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331 /   HD   OSCILLATORS

154  DF  ELECTROMECHANICAL RESONATOR {4}
158.~ Crystal {6}
159  DF  .~.~> Plural tube
160  DF  .~.~> With means to limit crystal current or voltage
161  DF  .~.~> With crystal substitution
162  DF  .~.~> Plural crystals in circuit
163  DF  .~.~> Crystal having three or more electrodes in circuit
164  DF  .~.~> Anode or cathode to grid crystal circuit

DEFINITION

Classification: 331/158

(under subclass 154) Subject matter wherein the frequency determining electrically driven material body is a crystal exhibiting the piezoelectric effect. Examples of such crystals are quartz, Rochelle salt, tourmaline or other crystal classes which do not possess a center of symmetry and wherein deformation of the crystal is proportional to the first power of the imposed electric field, the direction of deformation referring upon reversal of the field.

SEE OR SEARCH THIS CLASS, SUBCLASS:

70, for crystal oscillators provided with means to control the crystal temperature.

73, for crystal oscillators of the electron-coupled type.

139, for crystal oscillators of the bridge type.

155, for oscillators wherein a piezo crystal drives or is driven by the electromechanical resonator.

SEE OR SEARCH CLASS 310, Electrical Generator or Motor Structure,

311+, for piezoelectric transducers in general.

318, Electricity: Motive Power Systems,

116, for nonmagnetic motor systems which includes piezoelectric motor control systems.

322, Electricity: Single Generator Systems,

2, for nonmagnetic generator systems including piezoelectric type generators.

324, Electricity: Measuring and Testing,

56, for piezoelectric crystal testing.

332, Modulators,

26, for phase or frequency modulators utilizing an electromechanical resonant element which may be of the piezoelectric type.

333, Wave Transmission Lines and Networks, 148+, for wave delay networks that may include piezoelectric elements, and subclasses 187+ for electric wave filters utilizing piezoelectric crystals.

367, Communications, Electrical: Acoustic Wave Systems and Devices,

157+, for underwater vibration transducers of the piezoelectric type.

369, Dynamic Information Storage or Retrieval,

144, for a piezoelectric phonograph pickup.