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:
Oct. 04, 1994
Filed:
Dec. 23, 1993
Damon Morgan, Phoenix, AZ (US);
Horst Gempe, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A circuit for detecting a substance in motion. A light source (11) emits light which is received by a first photodetector (16) and a second photodetector (18). Each of the photodetectors (16) and (18) receives substantially equal light intensities from the light source (11). The first photodetector (16) generates a first output voltage (17) which corresponds to light intensity. The second photodetector (18) generates a second output voltage (19) which corresponds to light intensity. A differential amplifier (21) has a first input coupled to the first output voltage (17) and a second input coupled to the second output voltage (19). A moving substance (13) passing between the light source (11) and the first (16) or second (18) photodetectors generates a differential voltage which is amplified by the differential amplifier (21).