The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1976
Filed:
May. 30, 1975
Juho Yoneya, Tokyo, JA;
Isamu Inagaki, Tokyo, JA;
Sony Corporation, Tokyo, JA;
Abstract
An amplifier, for example, of a tape recording and reproducing apparatus, has a first smoothing power circuit for supplying DC power to operate the amplifying circuit when connected to an AC power source, and a second smoothing power circuit also adapted for connection to the AC power source for supplying DC power to operate other elements of the apparatus, such as, an oscillator for the bias signal to be applied to the recording head and/or an alarm for indicating the exhaustion of the tape, and also to energize a relay coil or the like by which change-over switches are actuated to their position for the recording mode of operation of the apparatus, with the first and second smoothing power circuits respectively having relatively large and small discharging time constants when disconnected from the AC power source so that, if the smoothing power circuits are disconnected from the AC power source while the apparatus is in its recording mode, the change-over switches may be returned to their positions for the reproducing or playback mode of the apparatus while the amplifying circuit is still operative to produce howling. Such howling is prevented by providing an amplifier, as aforesaid, with a holding circuit which detects the disconnection of the smoothing power circuits from the AC power source and, in response thereto, is effective to hold the change-over switches in their recording mode positions until the DC voltage applied to the amplifying circuit has declined sufficiently to render the latter inoperative.