JPS5466836A - Photometric circuit for camera - Google Patents

Photometric circuit for camera

Info

Publication number
JPS5466836A
JPS5466836A JP13398877A JP13398877A JPS5466836A JP S5466836 A JPS5466836 A JP S5466836A JP 13398877 A JP13398877 A JP 13398877A JP 13398877 A JP13398877 A JP 13398877A JP S5466836 A JPS5466836 A JP S5466836A
Authority
JP
Japan
Prior art keywords
operational amplifier
photo
voltage follower
current
follower circuit
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.)
Granted
Application number
JP13398877A
Other languages
Japanese (ja)
Other versions
JPS5858609B2 (en
Inventor
Saburo Numata
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.)
Fujinon Corp
Original Assignee
Fuji Photo Optical 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 Fuji Photo Optical Co Ltd filed Critical Fuji Photo Optical Co Ltd
Priority to JP13398877A priority Critical patent/JPS5858609B2/en
Publication of JPS5466836A publication Critical patent/JPS5466836A/en
Publication of JPS5858609B2 publication Critical patent/JPS5858609B2/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
    • H03F3/08—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light
    • H03F3/087—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only controlled by light with IC amplifier blocks

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

PURPOSE:To enhance the accuracy of photometry by coupling a voltage follower circuit to a feedback circuit. CONSTITUTION:Voltage follower circuit 16 in which the negative input terminal and output terminal of the operational amplifier 15 are short-circuited and the logarithm conversion diode 17 are inserted into the negative feedback circuit in which the divided point P of bleeder resistance 14 and the negative input terminal of the operational amplifier 10 are coupled. Thus, when the light of object is incident on photodetector 11, the photo-current produced is logrithm converted by diode 17, thereafter it enters the voltage follower circuit 16 to be absorbed. Then the potential relating to the photo-current is produced at the divided point P, and it is amplified by the operational amplifier 10. And, since the photo-current does not flow in at the divided point P, the gain of the operational amplifier 10 is maintained so constant that the accuracy of photometry can be enhanced.
JP13398877A 1977-11-08 1977-11-08 Photometering circuit for camera Expired JPS5858609B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13398877A JPS5858609B2 (en) 1977-11-08 1977-11-08 Photometering circuit for camera

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13398877A JPS5858609B2 (en) 1977-11-08 1977-11-08 Photometering circuit for camera

Publications (2)

Publication Number Publication Date
JPS5466836A true JPS5466836A (en) 1979-05-29
JPS5858609B2 JPS5858609B2 (en) 1983-12-26

Family

ID=15117748

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13398877A Expired JPS5858609B2 (en) 1977-11-08 1977-11-08 Photometering circuit for camera

Country Status (1)

Country Link
JP (1) JPS5858609B2 (en)

Also Published As

Publication number Publication date
JPS5858609B2 (en) 1983-12-26

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