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. 06, 1998
Filed:
May. 20, 1997
Hideki Wakamatsu, Hyogo, JP;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An impedance meter includes a floating type ammeter which measures a voltage across a current detection resistor and determines a current flowing therethrough. A balun eliminates the common mode voltage component in the high frequency range; and a differential amplifier eliminates the common mode voltage component in the low frequency range. The common mode rejection (common mode elimination) effect of the balun and differential amplifier crosses over at a crossover frequency where the impedance of an capacitor and the impedance of the balun are equal. As a result, the impedance meter is capable of measuring a broad range of impedances across a wide range of frequencies, both the low frequency and high frequency range.