JPS57178117A - Light measuring device - Google Patents

Light measuring device

Info

Publication number
JPS57178117A
JPS57178117A JP6492681A JP6492681A JPS57178117A JP S57178117 A JPS57178117 A JP S57178117A JP 6492681 A JP6492681 A JP 6492681A JP 6492681 A JP6492681 A JP 6492681A JP S57178117 A JPS57178117 A JP S57178117A
Authority
JP
Japan
Prior art keywords
output
opa
cop
switch
microcomputer
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
JP6492681A
Other languages
Japanese (ja)
Inventor
Yoshio Yuasa
Nobukazu Kawagoe
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 JP6492681A priority Critical patent/JPS57178117A/en
Publication of JPS57178117A publication Critical patent/JPS57178117A/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

Abstract

PURPOSE:To improve the processing performance of a microcomputer by integrating photometric signals for a constant time, and changing over the discharge currents thereof according to integrated quantities thereby controlling the counting time. CONSTITUTION:First when switches SW1, SW2 are opened, photometry is started via a photoelectric converter SPD, and the otput volage of an operational amplifier OPA is applied to comparators COP, COP'. A control circuit K emits a signal after a constant time to open the switch SW2, thereby holding the output volage of the amplifier OPA. When the output of the OPA during photometry exceeds a reference voltage Vr, the output of COP inverts, and a switch SW3 is closed by a changeover circuit X so that capacitors C1 and C2 are parallel connected. When the switch SW2 opens, SW4 and SW5 close and clock pulses are counted during the time until the output of the OPA goes to 0 by the discharge currents flowing through resistances R1, R2. Since the ranges are changed over, the processing efficiency of the microcomputer K is improved.
JP6492681A 1981-04-27 1981-04-27 Light measuring device Pending JPS57178117A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6492681A JPS57178117A (en) 1981-04-27 1981-04-27 Light measuring device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6492681A JPS57178117A (en) 1981-04-27 1981-04-27 Light measuring device

Publications (1)

Publication Number Publication Date
JPS57178117A true JPS57178117A (en) 1982-11-02

Family

ID=13272126

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6492681A Pending JPS57178117A (en) 1981-04-27 1981-04-27 Light measuring device

Country Status (1)

Country Link
JP (1) JPS57178117A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997044902A1 (en) * 1996-05-23 1997-11-27 Horst Ziegler Control circuit for recording the actuation of an optical key

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5195000A (en) * 1974-12-20 1976-08-20
JPS54133059A (en) * 1978-04-06 1979-10-16 Nec Corp Signal conversion circuit

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5195000A (en) * 1974-12-20 1976-08-20
JPS54133059A (en) * 1978-04-06 1979-10-16 Nec Corp Signal conversion circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997044902A1 (en) * 1996-05-23 1997-11-27 Horst Ziegler Control circuit for recording the actuation of an optical key

Similar Documents

Publication Publication Date Title
JPS5714726A (en) Measuring device for quantity of light
ES2069540T3 (en) ANALOG-DIGITAL CONVERTER.
US4245900A (en) Electronic exposure control apparatus
JPS57178117A (en) Light measuring device
GB1510733A (en) Photographic shutters
JPS5540422A (en) Exposure information generating circuit of single-lens reflex camera
JPS55120015A (en) Reflection photometric device for focal plane shutter
JPS5726922A (en) Voltage comparator
US4160160A (en) Circuit for integrating a quantity of light in an automatic control type flash unit
JPS5662231A (en) Control device for diaphragm of camera
JPS57101839A (en) Exposure device for wafer or photomask
US4588983A (en) Instantaneous gain changing analog to digital converter
GB1485530A (en) Photographic cameras
JPS5555267A (en) Diagnosis device of analog input device
JPS55127528A (en) Program control camera
JPS63282622A (en) Photometer
GB1085806A (en) Improvements in or relating to enlarging exposure meters and electronic timers
JPS5550165A (en) Spectrum display device
GB1465380A (en) Cameras employing interchangeable automatic exposure control devices
JPS57179823A (en) Integrating circuit for electronic shutter
JPS55106434A (en) Exposure adjusting device
JPS5774686A (en) Electronic watch
GB1272073A (en) An electric shutter control circuit for a photographic camera
JPS5783925A (en) Digital-to-analog converter
JPS57182723A (en) Automatic exposure controlling device