Distance compensated electrostatic voltmeter
Patent 4106869 Issued on August 15, 1978. Estimated Expiration Date: 
November 26, 1996. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
November 26, 1996. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3404341 3604925 3667036 3851247 InventorAssigneeApplicationNo. 05/744910 filed on 11/26/1976US Classes:399/73, Electrometer detail324/455, Corona induced324/457, ELECTROSTATIC FIELD324/72TESTING POTENTIAL IN SPECIFIC ENVIRONMENT (E.G., LIGHTNING STROKE)ExaminersPrimary: Pellinen, A. D.International ClassesG01R 15/16 (20060101)G01R 29/24 (20060101) G03G 15/00 (20060101) G01R 15/14 (20060101) AbstractA d.c. type electrostatic voltmeter for use in measuring voltage potentials on a surface such as the photoconductive surface of an electrostatic type reproduction machine. Circuitry is provided to automatically compensate for variations the electrometer probe-to-surface spacing, the circuitry including an a.c. signal source, a circuit to superimpose an a.c. signal from the source through the input and onto the d.c. signal output of the electrometer probe, an amplitude detector to detect changes in the a.c. signal source amplitude resulting from changes in the probe-to-surface spacing, a feedback control responsive to such amplitude changes to adjust the amplitude of the combined d.c./a.c. signal to maintain a prescribed a.c. amplitude, and a filter to thereafter remove the a.c. signal leaving the corrected d.c. signal. | |
