公开(公告)号：US3605030A

公开(公告)日：1971-09-14

申请号：US3605030D

申请日：1967-06-26

Applicant: BECKMAN INSTRUMENTS INC

Inventor： ELMORE MARSHALL D

IPC: G01R19/04 ,  H03F3/387 ,  H03F3/70 ,  H03K9/00 ,  H03F3/68

CPC classification number: H03F3/70 ,  G01R19/04 ,  H03F3/387

Abstract: A high sensitivity electrometer employing a capacitor to accumulate an electronic charge over a relatively long period and a first switch for coupling the charge to an operational amplifier over a short period. An inverting capacitively coupled amplifier drives a storage circuit comprising a peak detector and memory capacitor. A second switch synchronized with the first switch couples the storage circuit to the operational amplifier through a filter network to apply the stored peak voltage in the memory capacitor as a direct coupled electrometer input signal.

公开(公告)号：US3458705A

公开(公告)日：1969-07-29

申请号：US3458705D

申请日：1966-10-27

Applicant: BECKMAN INSTRUMENTS INC

Inventor： ELMORE MARSHALL D

IPC: G01L7/18 ,  G01F1/48 ,  G01F23/292 ,  G05D7/06 ,  G01N21/26

CPC classification number: G01F1/48 ,  G01F23/2925 ,  G05D7/0676 ,  Y10S250/901