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:
Feb. 03, 1981
Filed:
Jan. 04, 1979
John D Dick, Thiensville, WI (US);
Rollei of America, Inc., Littleton, CO (US);
Abstract
A first circuit arrangement including a zener diode coupled to the base of a transistor for keeping the transistor turned ON in response to the magnitude of voltage developed across a storage capacitor. The capacitor provides power to a photographic flash tube connected in series with a silicon controlled rectifier (SCR). After the flash tube is ignited, energy is drained from the charged capacitor until its voltage level reaches a predetermined magnitude at which time the zener diode becomes non-conducting, turning OFF the transistor, which causes a commutation of the SCR, terminating the flash of the flash tube. The capacitor is then recharged for preparation of the next flash operation. A second circuit arrangement utilizes a programmable unijunction transistor in which the voltage magnitude of the flash storage capacitor is followed by the gate of the unijunction transistor until the gate voltage reaches a corresponding voltage level preset at the anode of the unijunction transistor. The preset voltage level is a stored voltage which is proportional to the capacitor voltage immediately prior to flash actuation.