JPS5677724A - Photometric circuit - Google Patents

Photometric circuit

Info

Publication number
JPS5677724A
JPS5677724A JP15474279A JP15474279A JPS5677724A JP S5677724 A JPS5677724 A JP S5677724A JP 15474279 A JP15474279 A JP 15474279A JP 15474279 A JP15474279 A JP 15474279A JP S5677724 A JPS5677724 A JP S5677724A
Authority
JP
Japan
Prior art keywords
junction capacity
current
output
charged
potential
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
JP15474279A
Other languages
Japanese (ja)
Inventor
Masaaki Nakai
Masayoshi Sawara
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.)
Minolta Co Ltd
Original Assignee
Minolta 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 Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP15474279A priority Critical patent/JPS5677724A/en
Publication of JPS5677724A publication Critical patent/JPS5677724A/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)

Abstract

PURPOSE:To avoid the occurrence of the ringing with the junction capacity and then realize a quick reset of the photodiode to the normal state, by discharging once excessively the charged electric charge of the junction capacity of the photodiode and then giving the charging again later. CONSTITUTION:With supply of the noise signal from outside, the output of the operational amplifier OA1 has a high potential. Then the junction capacity of the photodiode PD is charged to turn the output potential of the OA1 to zero, and the output of the comparator OA2 becomes high potential. Thus the capacitor C1 is charged quickly via the transistors Q1 and Q2. As a result, the current of the Q3 increases, and the charged electric charge of the junction capacity of the PD is discharged gradually by the output current of the PD and the current of the Q3. In this case, the negative input potential of the OA1 is set lower than the positive potential, and thus the charged electric charge of the PD is discharged once and excessively. Then the charging is carried out again to the junction capacity of the PD via the D1 when the current of the Q3 becomes zero, thus obtaining the normal state.
JP15474279A 1979-11-28 1979-11-28 Photometric circuit Pending JPS5677724A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15474279A JPS5677724A (en) 1979-11-28 1979-11-28 Photometric circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15474279A JPS5677724A (en) 1979-11-28 1979-11-28 Photometric circuit

Publications (1)

Publication Number Publication Date
JPS5677724A true JPS5677724A (en) 1981-06-26

Family

ID=15590920

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15474279A Pending JPS5677724A (en) 1979-11-28 1979-11-28 Photometric circuit

Country Status (1)

Country Link
JP (1) JPS5677724A (en)

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