JPS5537954A - Photometry circuit of camera - Google Patents

Photometry circuit of camera

Info

Publication number
JPS5537954A
JPS5537954A JP11131778A JP11131778A JPS5537954A JP S5537954 A JPS5537954 A JP S5537954A JP 11131778 A JP11131778 A JP 11131778A JP 11131778 A JP11131778 A JP 11131778A JP S5537954 A JPS5537954 A JP S5537954A
Authority
JP
Japan
Prior art keywords
voltage
amplifier
circuit
input terminal
output
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
JP11131778A
Other languages
Japanese (ja)
Inventor
Tsutomu Kuriyama
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.)
Mamiya OP Co Ltd
Original Assignee
Mamiya Camera 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 Mamiya Camera Co Ltd filed Critical Mamiya Camera Co Ltd
Priority to JP11131778A priority Critical patent/JPS5537954A/en
Publication of JPS5537954A publication Critical patent/JPS5537954A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Exposure Control For Cameras (AREA)

Abstract

PURPOSE:To make it possible to improve the response delay of a photometry output at power-ON time due to a latch phenomenon by interposing a voltage follower circuit between a reference voltage source and logarithmic diode and also by connecting a time constant circuit to its input terminal. CONSTITUTION:Between constant-voltage circuit 2 and logarithmic diode LD, the voltage follower circuit of OP amplifier 3 is interposed and the voltage-dividing time constant circuit composed of resistances R1 and R2 and capacitor C2 is connected to the input terminal of the follower circuit, namely, the non-inversion input terminal. Therefore, reference operating voltage Vref of the photo current converter circuit composed of OP amplifier/photo diode PD and logarithmic diode LD is the output voltage of the voltage follower circuit by OP amplifier 3 and becomes equal to voltage VN at voltage-divislon point N of the time constant circuit. If the rise of the potential of non-inversion input terminal A of OP amplifier 1 when the power supply is put to work is equalized to that of its output VO by selecting delay time, the feedback operation of OP amplifier 1 starts as reference voltage Vref rises, so that output VO will immediately be in a steady state without being inverted.
JP11131778A 1978-09-12 1978-09-12 Photometry circuit of camera Pending JPS5537954A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11131778A JPS5537954A (en) 1978-09-12 1978-09-12 Photometry circuit of camera

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11131778A JPS5537954A (en) 1978-09-12 1978-09-12 Photometry circuit of camera

Publications (1)

Publication Number Publication Date
JPS5537954A true JPS5537954A (en) 1980-03-17

Family

ID=14558146

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11131778A Pending JPS5537954A (en) 1978-09-12 1978-09-12 Photometry circuit of camera

Country Status (1)

Country Link
JP (1) JPS5537954A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291238A (en) * 1991-06-24 1994-03-01 Nikon Corporation Photometering circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5291238A (en) * 1991-06-24 1994-03-01 Nikon Corporation Photometering circuit

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