Telefunken Electronic Gmbh

Licentia Patent-verwaltungs Gmbh

Gerhard Krumrein

Peter Mischel

Joachim Kuhlmann

Hartmut Hantsch

Jasbeer S Suri

Stephan Dermitzakis

A broad-band amplifier for the amplification of a photoelectric current triggered by a light signal, including a first transistor connected to receive the photoelectric current, a second transistor connected in series with the first one, a resistance connected between the base of the first transistor and the emitter of the second transistor, a third transistor and a fourth transistor which form a current mirror, the third transistor being connected in series with the second transistor, and a resistance located between the third transistor and ground.

Broad-band amplifier for the amplification of a photoelectric current

A protection circuit for an integrated circuit that is connected across a power source includes a first transistor and a zener diode or equivalent circuit arrangement for causing the first transistor to conduct if the integrated circuit receives an excessive voltage from the power source. A measuring resistor is connected to the emitter of the first transistor, and a voltage drop appears across the measuring resistor if the first transistor conducts. A comparator is provided to compare the voltage across the measuring resistor to a reference voltage. The output of the comparator drives the base of a second transistor, the emitter of which is connected to the collector of the first transistor and the collector of which is connected to the base of the first transistor. Current through the second transistor renders the first transistor more conductive.

Protection circuit for integrated circuits

A flasher unit is provided with a comparator whose output signal is fed to a pulse generator for producing the flash frequency signal, the comparator being supplied with a reference voltage at one input and a voltage dependent on the current passing through the flasher lamps at the other input and with a switch element which changes the reference voltage in accordance with the comparator output signal such that the comparator produces an output signal for the whole of the light up time of the lamps.

Flasher unit

The invention relates to a circuit for a computerized photoflash control which is supplied, preferably with the aid of a photographic element, with a current corresponding to the reflected light during the flash, from which an electrical quantity terminating the flash is derived. The invention consists in that the circuit contains a comparator, with a voltage derived from the current supplied at one of its inputs, while the other input of the comparator is supplied with an adjustable reference voltage. Connected to the output of the comparator is a switching path which is actuated by the comparator upon signal output, thereby terminating the flash.

Circuit for a computerized photoflash control

A circuit for a flasher unit comprises a flasher relay controlled by an astable multivibrator, the multivibrator having an RC-element with an inverter connected in front thereof, the inverter being controlled in response to the switching condition of the flasher relay.

Circuit for a flasher unit

A pulse generator comprises a comparator to the inputs of which are connected a capacitor chargeable by a power source and a voltage divider respectively, two transistors being connected to the output of the comparator, one to set the voltage ratio of the voltage divider and one to provide a discharge path for the capacitor and two additional transistors being selectively connected to the comparator output, one providing a different voltage ratio of the voltage divider and the other providing an independent discharge path for the capacitor.

Pulse generator

A monostable trigger arrangement comprises a monostable trigger stage controlled by a switch unit which is triggered by a control pulse to release a pulse from the monostable trigger stage and is returned to its untriggered state by an erase signal.

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Neuenstadt, Germany

Gerhard Krumrein