JPS54147878A - Lower noise preamplifier of ac type surface electrometer - Google Patents

Lower noise preamplifier of ac type surface electrometer

Info

Publication number
JPS54147878A
JPS54147878A JP5562178A JP5562178A JPS54147878A JP S54147878 A JPS54147878 A JP S54147878A JP 5562178 A JP5562178 A JP 5562178A JP 5562178 A JP5562178 A JP 5562178A JP S54147878 A JPS54147878 A JP S54147878A
Authority
JP
Japan
Prior art keywords
amplifier
input terminal
case
electric field
type surface
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
JP5562178A
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 JP5562178A priority Critical patent/JPS54147878A/en
Publication of JPS54147878A publication Critical patent/JPS54147878A/en
Pending legal-status Critical Current

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  • Measurement Of Current Or Voltage (AREA)

Abstract

PURPOSE: To prevent the generation of noise electric fields by shorting one of the input terminals of an operational amplifier and a metal case to become of the same potential.
CONSTITUTION: The AC current owing to the AC voltage corresponding to the electric field from the measuring object 8 detected by the detecting electrode 4 of an AC type surface electrometer is applied to the negative input terminal of the operational amplifier 5 of a preamplifier and is inversion-amplified, whereby the voltage corresponding to the measuring object electric field is generated. The positive input terminal of this amplifier 5 is held shorted to the metal case 6 of the amplifier 5 by a conductor 9, thus the positive input of the amplifier 5 and the case 6 become of the same potenital. Hence, the generation of the noise electric field between the negative input terminal to which the detecting current of the amplifier 5 is applied and the case 6 is prevented and the preamplifier is made lower in noise. The similar results may also be obtained even by letting the positive input terminal side be input and shorting the negative input terminal to the case.
COPYRIGHT: (C)1979,JPO&Japio
JP5562178A 1978-05-12 1978-05-12 Lower noise preamplifier of ac type surface electrometer Pending JPS54147878A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP5562178A JPS54147878A (en) 1978-05-12 1978-05-12 Lower noise preamplifier of ac type surface electrometer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP5562178A JPS54147878A (en) 1978-05-12 1978-05-12 Lower noise preamplifier of ac type surface electrometer

Publications (1)

Publication Number Publication Date
JPS54147878A true JPS54147878A (en) 1979-11-19

Family

ID=13003843

Family Applications (1)

Application Number Title Priority Date Filing Date
JP5562178A Pending JPS54147878A (en) 1978-05-12 1978-05-12 Lower noise preamplifier of ac type surface electrometer

Country Status (1)

Country Link
JP (1) JPS54147878A (en)

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