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:
Sep. 18, 1979
Filed:
Dec. 28, 1977
Francis H Gerhard, Anaheim, CA (US);
Gerald A Felper, Anaheim, CA (US);
Datapower, Inc., Santa Ana, CA (US);
Abstract
A gas discharge lamp is connected in parallel with an inductor and in series with a solid state switching device and a resistor, and this combination is connected across a DC voltage. This switching device is controlled by a monostable multivibrator, the input of which is connected to the output of a comparator amplifier sensing the difference between the voltage drop across the above mentioned resistor and the voltage of a variable reference voltage source. When the current through the inductor has increased to a point where the voltage drop across the resistor exceeds the voltage of the reference source, the comparator amplifier triggers the monostable multivibrator causing the solid state switching device to be turned off. This acts to collapse the magnetic field in the inductor thereby causing a large voltage to appear across the gas discharge lamp sufficient to light the lamp. At the end of the predetermined time period of the low output state of the monostable multivibrator, its output turns the solid state switching device on, allowing current to flow once again from the power supply through both the inductor and the lamp. The current flow through the lamp when the solid state switching device is on is in the opposite direction from the current flowing through the lamp when the solid state switching device is off. Thus, the lamp current is an alternating current. The intensity of the lamp is varied by varying the level of the reference voltage supplied to the comparator amplifier.