Patent GB-1454659-A (GB)
Title: Camera
IPC: H05B41/32
Filed: 1974-10-02
Abstract: 1454659 Cameras FRANKE & HEIDECKE GmbH trading as ROLLEI WERKE FRANKE & HEIDECKE 2 Oct 1974 [5 Oct 1973] 42744/74 Heading G2A A camera for optional operation with an electronic flashlight appliance and a current-ignited combustion flashlight lamp, comprises a contact  1, Fig. 1, for optionally receiving the adapters 25, 28 of the appliance 27 and the lamp 24 and connected in an electronic circuit which applies a voltage from a battery 3 to the contact and includes a transistor 20 which in operation is first made conductive, so that the contact 1 is short-circuited whereby the combustion lamp if used is ignited, and there-  after is made non-conductive so that the contact 1 is again subject to the battery voltage whereby the electronic flashlight appliance if used is operated. The battery 3 is also connected to an electronic control device 4 for a diaphragm shutter of the camera and including a photoelectric transducer 5 resistors 7, 9, an integration condenser 8, a measuring key 6, a starting switch 11, a camera release switch 10, a threshold value switch 12 an electromagnet 13 for closing the shutter and an indicator 14. When the switch 10 is closed a transistor 15 becomes conductive and a condenser 18 is discharged to render the transistor 20 non-conductive. When the shutter is released, the switch 11  is moved to contact 11a whereby the electronic control device 4 starts to measure the light and the collector of the transistor 15 becomes positive so that equalizing current flows via the condenser 18 to render the transistor 20 conductive and the contact 1 short-circuited. If the combustion flashlight is used it is at this time ignited. If the electronic control device 4 has received a sufficient quantity of light as measured by the condenser 8 and the resistor 9, the switch 12 reaches a specific potential and changes its zero-potential connection outlet 12d to its inlet 12b instead of its inlet 12a. The electromagnet 13 becomes de-energized to close the shutter and the transistor 20 becomes non-conductive so that contact 1 is again subject to battery voltage. If the electronic flash-light is used it is at this time operated. If the control device 4 has received an insufficient quantity of light the inlet 12a remains connected to zero-potential. The condenser 18 is gradually charged to cause the transistor 20 to become non-conductive and the electronic flashlight is operated. The resultant light reflected by the object to be photographed is sufficient to change over the inlet 12b to zero potential. To ensure that the combustion flashlight operates correctly a thyristor 35, Fig. 5, is used in combination with a transistor 34 and a resistor 33. When the transistor 20 becomes conductive there is a voltage drop at the resistor 33 due to discharge of the condenser 26 of the flashlight. This renders the transistor 34 conducting whereby the condenser 26 discharges through the thyristor 35. The electronic flashlight appliance is connected to a thyristor 29, Fig 4, the control grid of which is connected through a condenser 30 to the contact 1. A switch 32 is coupled to the switch-on trigger of the appliance to prevent inadvertant operation when the adapter 28 is attached to the camera. When the transistor 20 becomes non-conductive the battery voltage is  applied to the condenser 30 and the thyristor is triggered to operate the flashlight.