GB1359105A - Information holding apparatus - Google Patents
Information holding apparatusInfo
- Publication number
- GB1359105A GB1359105A GB3168672A GB3168672A GB1359105A GB 1359105 A GB1359105 A GB 1359105A GB 3168672 A GB3168672 A GB 3168672A GB 3168672 A GB3168672 A GB 3168672A GB 1359105 A GB1359105 A GB 1359105A
- Authority
- GB
- United Kingdom
- Prior art keywords
- transistor
- current
- cell
- light
- capacitor
- 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.)
- Expired
Links
- 239000003990 capacitor Substances 0.000 abstract 9
- 230000000694 effects Effects 0.000 abstract 2
- 230000000295 complement effect Effects 0.000 abstract 1
- 230000001419 dependent effect Effects 0.000 abstract 1
- 230000005669 field effect Effects 0.000 abstract 1
- 239000012528 membrane Substances 0.000 abstract 1
- 230000003287 optical effect Effects 0.000 abstract 1
- 238000010079 rubber tapping Methods 0.000 abstract 1
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
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
- G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
- G03B7/081—Analogue circuits
- G03B7/089—Analogue circuits for storage of exposure value in mirror reflex cameras
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C27/00—Electric analogue stores, e.g. for storing instantaneous values
- G11C27/02—Sample-and-hold arrangements
- G11C27/024—Sample-and-hold arrangements using a capacitive memory element
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/28—Modifications for introducing a time delay before switching
- H03K17/284—Modifications for introducing a time delay before switching in field effect transistor switches
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Photovoltaic Devices (AREA)
- Shutters For Cameras (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
Abstract
1359105 Electric shutter control circuits OLYMPUS OPTICAL CO Ltd 6 July 1972 [6 July 1971; 25 Dec 1971; 10 Jan 1972; 21 Jan 1972 (2); 22 April 1972] 31686/72 Heading G2A [Also in Division H3] An analogue store comprises a device which passes a current of value dependent upon information being received, a field effect transistor connected in series with the device, a capacitor connected between source and gate of the transistor such that the capacitor charges to a value which makes the transistor current equal to the device current and holds the current at this value. Fig.3 shows a camera shutter timer circuit including a solar cell 12 or a transistor Fig. 7, (not shown), controlled by the light input. When the switches of the store are in the position shown the cell is reverse biased and the capacitor 18 charges to such a value that the current through the transistor 6 is equal to the cell current. When the switches are reversed to initiate an exposure, the transistor current which is held by the capacitor at the same value, charges a capacitor 100 until a transistor 36 conducts and so terminates the exposure. Variations of the store are described with reference to Fig. 1 and to Figs. 4-12 (not shown). In Fig. 1, switches 10, 10a and 3 are replaced by a changeover switch which connects the output current either to the cell or to the load. Fig. 5 is similar but of complementary conductivity. In Fig. 4 the switch 10a, which by-passes the output, is omitted. Fig. 6 uses an enhancement type M.O.S. transistor, switch 18 being connected between drain and gate and Fig. 7 is a similar circuit replacing the cell with a transistor having its base current controlled by the light. Figs. 8 and 9 use P and N channel junction F.E.Ts respectively and Fig.10 provides a diode in series with the cell to prevent it being discharged during read-out and uses a changeover switch instead of 11a and 18. Fig.11 is similar to Fig. 10 but has multi-vibrator control of switching and a similar circuit, Fig.12, adds a transistor in series with switch 18 to allow the gate and source potential to rise by the voltage across the cell. The circuit of Fig. 3 is adapted for use in a through-the-lens camera for controlling the exposure, the light level being measured before operation of the shutter release and stored during exposure, lamps being provided to indicate excessive or insufficient light. The light level is indicated by the current through transistor 6 when the switches in the light unit 20 are as shown. In the intermediate position of the release button the switches 3, 11a and 10a are changed over and contact 26 is as shown. The current from transistor 6 charges a capacitor 100 which is periodically discharged by a transistor 30 controlled by a multi-vibrator 76. The resulting pulses are applied via transistors 36 to 40 and 42 which supply two inputs of a bi-stable circuit 90. Other inputs receive the output from transistor 60 of the multi-vibrator and fixed length pulses from 81. The resulting effect is that if the light is within the usable range one of the lamps 92, 94 is lit. If the light is too large the other is lit and if too low the lights alternate. If the shutter release control is moved further the reflector of the camera is moved away, contact 18 is opened to store the light level because the cell is not now receiving light and contact 26 is changed over. A focal plane shutter is opened by solenoid 58 and when capacitors 10 have charged sufficiently to render a transistor 36 conducting the solenoid is de-energized releasing the rear membrane of the shutter to effect closure. The tappings on resistor 46 adjust for film speed and on capacitor 100 for aperture. Fig. 11 illustrates an alternative arrangement of the multi-vibrator and light measuring circuit which omits the voltage across the "load" (14) from the capacitor circuit and Fig. 12 includes an additional transistor in series with switch 18 which is switched off when 30 is off so as to allow the gate and source potentials to rise by the voltage across the cell.
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP46049774A JPS5110978B1 (en) | 1971-07-06 | 1971-07-06 | |
JP33472A JPS5327928B2 (en) | 1971-12-25 | 1971-12-25 | |
JP1972005926U JPS5316896Y2 (en) | 1972-01-10 | 1972-01-10 | |
JP1972009375U JPS5131650Y2 (en) | 1972-01-21 | 1972-01-21 | |
JP1972009376U JPS5119881Y2 (en) | 1972-01-21 | 1972-01-21 | |
JP1972048011U JPS5120772Y2 (en) | 1972-04-22 | 1972-04-22 |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1359105A true GB1359105A (en) | 1974-07-10 |
Family
ID=27547524
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB3168672A Expired GB1359105A (en) | 1971-07-06 | 1972-07-06 | Information holding apparatus |
Country Status (3)
Country | Link |
---|---|
US (1) | US3742830A (en) |
DE (1) | DE2233269A1 (en) |
GB (1) | GB1359105A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2482048A1 (en) * | 2011-01-28 | 2012-08-01 | Legrand GmbH | Method and device for measuring a lighting level and twilight switch comprising same |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4041327A (en) * | 1976-08-02 | 1977-08-09 | Gte Automatic Electric (Canada) Ltd. | Sense point circuit |
US4447746A (en) * | 1981-12-31 | 1984-05-08 | International Business Machines Corporation | Digital photodetectors |
EP0308169B1 (en) * | 1987-09-14 | 1994-12-28 | Fujitsu Limited | Charge injection circuit |
JPH07175535A (en) * | 1993-12-16 | 1995-07-14 | Nec Corp | Power circuit for fet amplifier |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1601954A (en) * | 1968-03-08 | 1970-09-21 | ||
US3633473A (en) * | 1969-11-10 | 1972-01-11 | Copal Co Ltd | Exposure control apparatus for photographic camera |
NL7014135A (en) * | 1970-09-25 | 1972-03-28 |
-
1972
- 1972-06-30 US US00267979A patent/US3742830A/en not_active Expired - Lifetime
- 1972-07-06 DE DE2233269A patent/DE2233269A1/en active Pending
- 1972-07-06 GB GB3168672A patent/GB1359105A/en not_active Expired
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2482048A1 (en) * | 2011-01-28 | 2012-08-01 | Legrand GmbH | Method and device for measuring a lighting level and twilight switch comprising same |
Also Published As
Publication number | Publication date |
---|---|
US3742830A (en) | 1973-07-03 |
DE2233269A1 (en) | 1973-01-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PS | Patent sealed [section 19, patents act 1949] | ||
PCNP | Patent ceased through non-payment of renewal fee |