JPS5554447A - Surface electrometer on negative feedback alternating- current type - Google Patents

Surface electrometer on negative feedback alternating- current type

Info

Publication number
JPS5554447A
JPS5554447A JP7491178A JP7491178A JPS5554447A JP S5554447 A JPS5554447 A JP S5554447A JP 7491178 A JP7491178 A JP 7491178A JP 7491178 A JP7491178 A JP 7491178A JP S5554447 A JPS5554447 A JP S5554447A
Authority
JP
Japan
Prior art keywords
signal
voltage
operational amplifier
synchronous detection
converted
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP7491178A
Other languages
Japanese (ja)
Inventor
Minoru Aoki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP7491178A priority Critical patent/JPS5554447A/en
Publication of JPS5554447A publication Critical patent/JPS5554447A/en
Pending legal-status Critical Current

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  • Measurement Of Current Or Voltage (AREA)

Abstract

PURPOSE: To lighten a load on a converting method and also to compose a synchronous detection circuit, etc., of a semiconductor, by sampling and holding a signal from the current-voltage converting method by a signal out of phase by a half cycle synchronizing with cycles of a modulating method.
CONSTITUTION: Electric field Ex generated between measured body 11 and detection electrode 12 by surface potential Vx is changed into flux current Ix by vibrating electrode 10 and then converted into voltage signal by operational amplifier OP1. Although signal V01 is converted into voltage signal V02 by operational amplifier OP2, operational amplifier OP3, capacitor C3 and variable resistance R3 makes an adjustment to a phase needed for synchronous detection, namely, the generation of gate pulses VP1 and VP2 agrees with the bottom of valley of waveforms of voltage signals V03 and V04. Therefore, when pulses VP1 and VP2 are generated, turning switch elements S1 and S2 ON charges capacitor C5 to the peak values of valleys of voltage signals V03 and V04 and the values are stored even if elements are switched OFF, so that synchronous detection output voltage VT can be obtained.
COPYRIGHT: (C)1980,JPO&Japio
JP7491178A 1978-06-22 1978-06-22 Surface electrometer on negative feedback alternating- current type Pending JPS5554447A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7491178A JPS5554447A (en) 1978-06-22 1978-06-22 Surface electrometer on negative feedback alternating- current type

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7491178A JPS5554447A (en) 1978-06-22 1978-06-22 Surface electrometer on negative feedback alternating- current type

Publications (1)

Publication Number Publication Date
JPS5554447A true JPS5554447A (en) 1980-04-21

Family

ID=13561032

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7491178A Pending JPS5554447A (en) 1978-06-22 1978-06-22 Surface electrometer on negative feedback alternating- current type

Country Status (1)

Country Link
JP (1) JPS5554447A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103616553A (en) * 2013-12-05 2014-03-05 上海高试电气科技有限公司 Short circuit large current waveform fitting method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103616553A (en) * 2013-12-05 2014-03-05 上海高试电气科技有限公司 Short circuit large current waveform fitting method

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