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:
Jun. 28, 1983
Filed:
Sep. 25, 1980
Tino Celio, Ambri, CH;
Hans Ott, Regensdorf, CH;
GRETAG Aktiengesellschaft, Regensdorf, CH;
Abstract
A measuring instrument, such as a densitometer, that uses an incandescent lamp as a measuring light source is provided with a control stage for energizing the light source upon switch-on to prevent overshoot of the desired luminous flux from the lamp that occurs if the final energizing voltage is applied immediately. The control stage includes an amplifier with a negative feedback network that is fed with a reference voltage via a switch. The feedback network includes a resistance-capacitance element and is responsive to closure of the switch to establish the initial lamp energizing voltage at 1-2% below its final value and to allow the voltage to rise to its final value over a period of 1 to 3 seconds.