Photographic exposure setting device

Claim 2

A photographic exposure setting device for a camera having a shutter, the device comprising: a power source (5) having positive and negative supply buses (A, B); a. a voltage divider (4) for determining the sensitivity range of a photographic material selected for photography, respective leads of said divider being connected to respective ones of said supply buses; b. a first integrating timing RC circuit (1a) having a center tap, leads of said circuit being connected to respective ones of said supply buses, the illumination of a photoresistor (3) in said circuit (b) determining a time constant of said circuit (b), which constant is an optimum exposure time for a given illumination intensity of the object being photographed, from which the reflected light is incident upon said photoresistor; c. an exposure time setting unit (1) for a camera having a shutter, said exposure time setting unit having two inputs (I, II) and two outputs (III, IV), one (I) of said inputs being connected to said center tap of the circuit (b), the other (II) of said inputs of the unit (c) being connected to the center tap of said divider (a) for setting an operation threshold of said unit (c), depending upon the sensitivity range of the selected material; d. a voltage stabilizer (13), having inputs connected to respective ones of said supply buses; e. a second integrating timing RC circuit (10a), one of its leads being connected to one output of said stabilizer (d) in order to stabilize its time constant, another lead of said circuit (e) being connected to said negative supply bus; f. a first transistor switch (14) having two inputs, one thereof being connected to one (IV) of said outputs of the unit (c); g. an insufficient illumination indicating unit (7) having two inputs (I, II) and two outpus (III, IV), there being connected to one (I) of said inputs of the unit (g) the center tap of said circuit (e), whereas an output of said switch (f) is connected to the other (II) of said inputs of the unit (g); one (IV) of said outputs of the unit (g) being connected to the other of said inputs of the switch (f), another one (III) of said ouputs of the unit (g) being connected to said positive supply bus via an indicator lamp (16) for warning about unfavorable conditions for photography; h. a second transistor switch (15), also having two inputs, one thereof being connected to said one (IV) output of the unit (c); i. a third integrating timing RC circuit (11a), one of its leads being connected to an output of said stabilizer (d) to stabilize its time constant, another lead of said circuit (i) being connected to said negative supply bus; j. an excessive illumination indicating unit (8) having two inputs (I, II) and two outputs (III, IV), the center tap of said circuit (i) being connected to (I) of said inputs, whereas an output of said switch (h) is connected to another one (II) of said inputs of the unit (j); one (IV) of said outputs of the latter being connected to the other of said inputs of the switch (h), another of said outputs of the limit (j) being connected to said positive supply bus via indicator lamp (17) for warning about unfavorable conditions for photography; and k. an actuator (6) connected to the shutter of the camera for closing and opening said shutter, one lead of said actuator being connected to the other output (III) of said unit (c), its other lead being connected to said positive supply bus.

Claim 3

The photographic exposure setting device as defined in claim 1, further comprising (1) an exposure time stabilizer having two outputs, one of the latter being connected to said one input (I) of the unit (c) via a capacitor (2) of said circuit (b), its other output being connected to said positive supply bus via a resistor (20), said exposure time stabilizer (1) having a flip-flop including transistors (18, 19) whose outputs are at their collectors, and a transistor (22) interposed between the emitters of said transistors of the flip-flop and said negative supply bus, and operating as diodes to effect a shift in the input voltage across said one (I) input of the unit (c).

Claim 4

A photographic exposure setting device for a camera having a shutter, the device comprising: a power source (5) having a positive and negative supply buses (A, B); a. an exposure time setting unit (1) for a camera having a shutter, said exposure time setting unit having two inputs (I, II) and two outputs (III, IV); said unit (a) including a threshold amplifier (25) whose two inputs are connected to said inputs (I, II) of the unit (a); said amplifier including serially connected transistors (28 to 31) constituting a common-emitter circuit, the first transistor (28) operating in the linear mode, whereas the remaining transistors (29 to 31) operate in the switching mode; one input of said amplifier constitute one (I) of said inputs of the unit (a), being the base of said first transistor; another input of said amplifier, which forms another one (II) of said inputs of the unit (a), being linked to the interconnected emitters of two (29, 31) of said transistors, the output of said amplifier being linked to the collector of the last one (31) of said transistors; b. means (26) for shifting the output voltage level of said amplifier (25), said means constituting a cascade of transistors (36 to 39) serially interconnected by way of their base - emitter junctions, the base of the first one (36) of said last-named transistors being connected to said output of the amplifier (25); c. a current amplifier (27) whose input is connected to the emitter of the last one (39) of said transistors of the means (b), said current amplifier including serially interconnected transistors (42 to 45) constituting a common-emitter circuit and operating in the switching mode, one output of said current amplifier (27) being the collector of the last one (45) of its transistors, another output thereof being the collector of one (43) of said transistors, both said last-named outputs constituting said outputs (III, IV) of the unit (a); d. three integrating timing RC circuits (1a, 10a, 11a), leads of a first one (1a) of said circuits being connected to respective ones of said supply buses, whereas a center tap of said first circuit (1a in d) is connected to said one (I) input of the unit (a); e. a voltage divider (4) whose leads are connected to respective ones of said supply buses, a center tap of said divider (e) being connected to said other input (II) of the unit (a); f. a voltage stabilizer (13) also connected to said positive supply bus via a ballast current-limiting resistor (66), said stabilizer (f) including at least two transistors (64, 65) that are serially interconnected via their base - emitter junctions; g. a first transistor switch (14) having two inputs and one output, one of said inputs being connected to one (IV) of said outputs of the unit (a); said second circuit (10a in d) being connected to the output of said stabilizer (f) and to said negative supply bus; h. an insufficient illumination indicating unit (7) having two inputs (I, II) and two outputs (III, IV), there being connected to one (I) of said inputs of the unit (b) the center tap of said second circuit (10a in d), whereas an output of said switch (g) is connected to the other (II) of said inputs of the unit (h); the latter including a threshold current amplifier including serially interconnected transistors (48 to 50) constituting a common-emitter circuit and operating in the switching mode; one input of said threshold current amplifier, which forms said one input (I) of the unit (h), being the base of the first one (48) of said transistors, the other input of said threshold current amplifier, which forms said other input (II) of the unit (h), being the base of one (49) of said transistors, one output of said threshold current amplifier, and of said unit (h), being common with the collector of the last one (50) of said transistors in the current amplifier, another output of the latter being the collector of said last transistor (50), said last-named other output being connected to said other input of the switch (g); i. a second transistor switch (15), having two inputs and one output, one of said inputs being connected to said one output (IV) of the unit (a); said third circuit (11a in d) having its leads connected to said output of the stabilizer (f) and said negative supply bus; j. an excessive illumination indicating unit (8) having two inputs (I, II) and two outputs (III, IV), there being connected to one (I) of said inputs the center tap of said third circuit (11a in d), another one (II) of said inputs being connected to said output of the switch (i), said unit (j) including a threshold current amplifier including serially interconnected transistors (56 to 59) that constitute a common-emitter circuit and operate in the switching mode, one input of said last-named threshold current amplifier, which forms said one input (I) of the unit (j), being the base of one (57) of said transistors, one output of the same amplifier, and of the unit (j), being the collector of the last one (59) of said transistors in the threshold current amplifier, said other output being the collector of another one (58) of said transistors, said other output being connected to said other input of the switch (i); k. an actuator (6) connected between said positive supply bus and said one output (III) of the unit (a); and l. two indicator lamps (16, 17), each having one of its terminals connected to said positive supply bus, the other terminals being respectively connected to said one outputs of the units (h and j).

Claim 5

A photographic exposure setting device for a camera having a shutter, the device comprising: a power source (5) having a positive and negative supply buses (A, B); a. an exposure time setting unit (1) for a camera having a shutter, said exposure time setting unit having two inputs (I, II) and two outputs (III, IV); said unit (a) including a threshold amplifier (25) whose two inputs are connected to said inputs (I, II) of the unit (a); said amplifier including serially connected transistors (28 to 31) constituting a common-emitter circuit, the first transistor (28) operating in the linear mode, whereas the remaining transistors (29 to 31) operate in the switching mode; one input of said amplifier constitute one (I) of said inputs of the unit (a), being the base of said first transistor; another input of said amplifier, which forms another one (II) of said inputs of the unit (a), being linked to the interconnected emitters of two (29, 31) of said transistors, the output of said amplifier being linked to the collector of the last one (31) of said transistors; b. means (26) for shifting the output voltage level of said amplifier (25), said means constituting a cascade of transistors (36 to 39) serially interconnected by way of their base - emitter junctions, the base of the first one (36) of said last-named transistors being connected to said output of the amplifier (25); c. a current amplifier (27) whose input is connected to the emitter of the last one (39) of said transistors of the means (b), said current amplifier including serially interconnected transistors (42 to 45) constituting a common-emitter circuit and operating in the switching mode, one output of said current amplifier (27) being the collector of the last one (45) of its transistors, another output thereof being the collector of one (43) of said transistors, both said last-named outputs constituting said outputs (III, IV) of the unit (a); d. three integrating timing RC circuits (1a, 10a, 11a), leads of a first one (1a) of said circuits being connected to respective ones of said supply buses, whereas a center tap of said first circuit (1a in d) is connected to said one (I) input of the unit (a); e. a voltage divider (4) whose leads are connected to respective ones of said supply buses, a center tap of said divider (e) being connected to said other input (II) of the unit (a); f. a voltage stabilizer (13) also connected to said positive supply bus via a ballast current-limiting resistor (66), said stabilizer (f) including at least two transistors (64, 65) that are serially interconnected via their base - emitter junctions; g. a first transistor switch (14) having two inputs and one output, one of said inputs being connected to one (IV) of said outputs of the unit (a); said second circuit (10a in d) being connected to the output of said stabilizer (f) and to said negative supply bus; h. an insufficient illumination indicating unit (7) having two inputs (I, II) and two outputs (III, IV), there being connected to one (I) of said inputs of the unit (b) the center tap of said second circuit (10a in d), whereas an output of said switch (g) is connected to the other (II) of said inputs of the unit (h); the latter including a threshold current amplifier including serially interconnected transistors (48 to 50) constituting a common-emitter circuit and operating in the switching mode; one input of said threshold current amplifier, which forms said one input (I) of the unit (h), being the base of the first one (48) of said transistors, the other input of said threshold current amplifier, which forms said other input (II) of the unit (h), being the base of one (49) of said transistors, one output of said threshold current amplifier, and of said unit (h), being common with the collector of the last one (50) of said transistors in the current amplifier, another output of the latter being the collector of said last transistor (50), said last-named other output being connected to said other input of the switch (g); i. a second transistor switch (15), having two inputs and one output, one of said inputs being connected to said one output (IV) of the unit (a); said third circuit (11a in d) having its leads connected to said output of the stabilizer (f) and said negative supply bus; j. an excessive illumination indicating unit (8) having two inputs (I, II) and two outputs (III, IV), there being connected to one (I) of said inputs the center tap of said third circuit (11a in d), another one (II) of said inputs being connected to said output of the switch (i), said unit (j) including a threshold current amplifier including serially interconnected transistors (56 to 59) that constitute a common-emitter circuit and operate in the switching mode, one input of said last-named threshold current amplifier, which forms said one input (I) of the unit (j), being the base of one (57) of said transistors, one output of the same amplifier, and of the unit (j), being the collector of the last one (59) of said transistors in the threshold current amplifier, said other output being the collector of another one (58) of said transistors, said other output being connected to said other input of the switch (i); k. an actuator (6) connected between said positive supply bus and said one output (III) of the unit (a); and l. two indicator lamps (16, 17), each having one of its terminals connected to said positive supply bus, the other terminals being respectively connected to said one outputs of the units (h and j).