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. 31, 1989
Filed:
Oct. 28, 1986
Bruce T Williams, Lockport, NY (US);
Other;
Abstract
A non-contacting electrostatic voltage follower employs a vibrating capacitance detector coupled to a measured surface containing both wideband electrostatic A.C. data and D.C. potentials. A detector amplifier having an inverting input is connected to the detector, while its output is connected to the input of a high bandwidth amplifier. A first feedback path is provided from the output of the high bandwidth amplifier to the non-inverting input of the detector amplifier which provides both a signal which is equal to and follows the wideband electrostatic A.C. potentials on the measured surface, and a signal, at the vibrating capacitance modulation frequency, representative of the D.C. potential of the measured surface. A second feedback path is provided including a demodulator and integrator to monitor the first feedback path to provide a D.C. correction signal to the high bandwidth amplifier to null the signal on the first feedback path which is representative of the vibrating capacitance modulation of the D.C. potential of the measured surface. As a result, the monitored signals on the first feedback path will be driven to, follow, and exactly match all wideband A.C. and D.C. electrostatic data on the measured surface. An electrostatic probe employs a vibrating transparent detector element and is disposed in a path of radiation whcih is directed onto a measured electrostatic surface.