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:
May. 22, 2012
Filed:
Nov. 10, 2006
George D. Goodman, Phoenixville, PA (US);
Edward J Harris, Pottstown, PA (US);
George D. Goodman, Phoenixville, PA (US);
Edward J Harris, Pottstown, PA (US);
Halliburton Energy Services, Inc., Houston, TX (US);
Abstract
A displaced electrode amplifier ('DEA') for measuring signals from high impedance sources. The amplifier may include an operational amplifier ('op-amp') configured as a unity gain buffer, with a feedback path to the non-inverting input to at least partly compensate for a parasitic input shunt impedance. In cases where the device is to measure AC signals in high ambient temperatures, the non-inverting input may be coupled via a large resistance to a ground reference that is driven with a second feedback signal to magnify the effective value of the large resistance. Where a differential configuration is desired, one or more tuning resistors may be provided to match responses of different input buffer stages, thereby maximizing the common mode rejection. The disclosed amplifier is suitable for use in oil-based mud resistivity imaging tools but is also suitable for other applications.