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. 14, 1992
Filed:
May. 22, 1991
Shinji Hirata, Toyonaka, JP;
West Electric Co., Ltd., Osaka, JP;
Abstract
An I.G.B.T. (Insulated Gate Bipolar Transistor) driven electronic flash unit includes a control switch for controlling an off-operation of the I.G.B.T. The control switch has a first terminal for receiving a light-emission stopping command of a very short pulse width, a second terminal supplied with a collector electrode voltage of the I.G.B.T. connected in series with a flash tube, third and fourth terminals respectively connected with gate and emitter electrodes of the I.G.B.T., which short-circuits the third and fourth terminals upon receiving the light-emission stopping command at the first terminal, and maintains the short-circuit operation as long as it receives the collector electrode voltage of the I.G.B.T. at the second terminal.