Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB956428A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Parlophone Records Ltd
Original Assignee
Gramophone Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gramophone Co LtdfiledCriticalGramophone Co Ltd
Priority to GB956428ApriorityCriticalpatent/GB312444A/en
Publication of GB312444ApublicationCriticalpatent/GB312444A/en
H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
H03H9/02—Details
H03H9/05—Holders; Supports
H03H9/0504—Holders; Supports for bulk acoustic wave devices
Abstract
312,444. Gramophone Co., Ltd., Whitaker, A., and Eccles, W. H. March 29, 1928. Light-valves.- A piezo-electric crystal, maintained in vibration at high frequency, has its damping varied at acoustic or low frequency. As shown, the crystal 1 silvered on its opposite faces is supported on an insulating plate 5 between the poles 2, 3 of an electromagnet. A coil 4 mounted on the magnet yoke carries audio-frequency currents which vary the magnetic flux through the crystal and so vary the eddy currents in its silvered surfaces. The damping, and therefore the amplitude of the crystal vibration, is thus varied at audiofrequency. In a modification, the audio-frequency currents set a diaphragm in vibration, and the diaphragm varies the damping of the crystal either by variable pressure on, or by variable air spacing from, the crystal surface. The apparatus may be used for modulating a beam of light in accordance with sounds. Specification 305,074 is referred to in the Provisional Specification.
GB956428A1928-03-291928-03-29Improvements in or relating to piezo-electric devices
ExpiredGB312444A
(en)
Improvements relating to the mounting of vibrating reeds, more particularly for use in connection with electromagnetic gramophone pick-ups, loud speakers and the like
Improvements relating to the mounting of vibrating reeds, more particularly for use in connection with electromagnetic gramophone pick-ups, loud speakers and the like