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. 23, 1997
Filed:
Jun. 23, 1995
Claude Abraham, Stow, OH (US);
Philip C Dolsen, Mentor, OH (US);
Ardac, Inc., Eastlake, OH (US);
Abstract
A current boosted positive feedback logarithmic transresistance amplifier is provided for currency validators. The amplifier has a photo-diode capable of producing a current in response to light, connected to an operational amplifier having both a positive and a negative feedback branch. A logarithmic density amplifier having a feedback resistor and a log diode connected in shunt with the resistor as a dynamic feedback to the amplifier is connected to the positive feedback branch of the current boosting amplifier by way of the log diode. The summing action at the inputs of the current boosting amplifier result in a current at the log diode that is a direct multiple of the current in the photo-diode.