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:
Jan. 12, 1999
Filed:
Sep. 11, 1996
Klaas J Lulofs, Drachten, NL;
Petrus J Bremer, Drachten, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A hair-care appliance measures the moistness of the hair by measuring the resistance (R.sub.x) of the hair between measurement electrodes (14A/14B). The hair resistance (R.sub.x) is included in a T network comprising a first resistor (20) driven by a voltage source (28) and a second resistor (24). The signal current (I.sub.s) through the second resistor is measured and converted into a measurement signal (MS) by a converter (30). As a result of the use of the T network a comparatively large resistance variation of the hair resistance (R.sub.x) is required for a given amplitude variation in the signal current (I.sub.s). This allows measurements over a wider resistance range while the resolution is maintained.