Abstract: The circuit includes sensors for supplying electrical signals indicative of the current flowing in the field winding of the generator in operation and a control circuit operatively connected to the sensors. The control circuit is arranged to control the transistor which drives the field winding so that the voltage at the battery terminals remains substantially constant with variations in the current supplied to the battery by the generator.

Abstract: A monitoring circuit for an electrical generator for recharging a motor vehicle battery. The monitoring circuit includes a driver transistor, a field coil current sensor, and driver circuit. The collector-emitter path of the driver transistor is connected in series to the field coil of the generator and a direct current voltage source. The field coil current sensor provides a signal indicative of the current flowing in the field coil. The driver circuit drives the transistor as a function of the voltage produced by the generator and the signal provided by the field coil current sensor. The driver circuit includes a detector circuit and a processing and comparison circuit. The detector circuit is connected to a phase of the generator and provides a signal indicative of the generator's rotation speed.

Abstract: The voltage-regulator circuit includes:a driver transistor whose collector-emitter path is in series with the field winding between two poles of a source of a direct-current voltage, anda control circuit adapted to drive the transistor in an on-off manner in dependence on the value assumed by the voltage supplied by the generator in comparison with a reference voltage and in dependence on the field current detected by a resistor connected to the transistor.

Abstract: The device includes a circuit for generating signals indicative of a reference current which is variable in steps and, during successive time intervals defined by a clock-signal generator, decreases according to respective predetermined functions as the voltage detected across the lamp increases, these functions corresponding substantially to respective predefined constant values of the power supplied to the lamp, and a differential comparator circuit which compares the values of the reference current generated with the current detected in the lamp and generates an error signal in dependence on the difference between them. The error signal can be used to control the device for supplying the lamp.

Abstract: A system for recharging a battery includes a current generator, a switch operable by a key and connected to the battery, an indicator lamp connected in series with the switch, and a voltage regulator with first and second inputs connected to the output of the generator and to the lamp, respectively. The regulator includes a circuit for regulating the current supplied to the field winding of the alternator in dependence on the voltage supplied by the generator, a supply circuit for supplying the voltage regulator circuit, and control circuit for enabling the supply circuit to operate when a current is flowing in the lamp and when the generator is in operation. The control circuit includes a comparator connected to the second input of the regulator, and hence to the lamp, and adapted to supply an enabling signal to the supply circuit when the voltage at the second terminal exceeds a predetermined threshold.

Abstract: A print unit for an electronic typewriter comprising a removable character-carrying disc with flexible spokes which is operated by a selector motor which in turn is controlled by a control circuit. The character-carrying disc is provided with a plurality of reflective identification plates and a recognition circuit detects the pattern of the reflective plates present in selected ones of a series of predetermined angular sectors of the disc to identify some characteristics of the disc, e.g. typing pitch and character set. The angular position of the disc is detected by a position transducer which generates a position signal for the control circuit having a period which is double the angular distance between two contiguous character-carrying spokes discriminating the spokes at even positions from those at odd positions.

Abstract: An optical transducer for detecting the position of a rotary or translatory member comprises a light source, a photodetector group, and a shutter provided with a series of transparent elements spaced by opaque regions and interposed between the light source and the photodetector group. The photodetector group comprises an integrated circuit, on a surface of which is disposed a plurality of photovoltaic cells, each having an area which is a fraction of the area of each transparent element. The cells are divided into four groups to generate as many electrical signals which are out of phase relative to each other by 90.degree. and which are indicative of the position of the shutter with respect to the position of the photodetector group and the light source. The cells are disposed symmetrically with respect to a central radially extending optical axis, and in such a way that the barycenter of the areas of each of the four groups is included in the central optical axis.

Abstract: A device for controlling the rotary movement of a platen roller of a typewriter comprises a bidirectional electric motor coupled to the platen by a worm gear and gear wheel and a pair of knobs which are disposed at the sides of the platen and which are rotatable with respect thereto. The knobs are fixed to a bar which extends rotatably through the platen roller and carries the gear wheel. Selective bidirectional rotation of the knobs causes corresponding rotary movement of a disc in a transducer. The disc has a toothed sector in mesh with the gear wheel and is the moving part of a rotary switch which generates electrical signals which determine both the power supply to the electric motor and the direction of rotation thereof. Small degrees of rotary movement of the knobs against a first spring force establish continuous rotary movement of the platen roller at low speed. A further slight rotary movement of the knobs against a stronger spring force establishes rotary movement of the platen at high speed.

Abstract: A direct-current electric motor (29) used for, for example, positioning a printing device in an office machine, is controlled by an arrangement comprising a microprocessor (40) which causes the motor digitally to perform accelerations and/or decelerations to maintain it close to a desired speed programmed in relation to the distance to be completed. Control between the actual speed of the motor and the desired speed is effected utilizing the timing signals (FTA, STB) generated by a transducer (35) connected to the motor. During a first phase, the microprocessor compares the times taken to complete a series of angular steps of rotation, the steps following a schedule of decreasing size with stored reference times and effects accelerations and decelerations of durations proportional to any discrepancies.

Abstract: An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure comprises a disc 13 mounted rotatably within a casing. The disc is provided with a plurality of opaque radial regions 19 which are spaced by transparent regions 18 which transmit the light emitted by a light source mounted on the casing. The light is received by a photodetector element 25 comprising a support plate 28 on which is disposed a multiplicity of photovoltaic cells 26 each having an area which is fraction of the area of each transparent region of the disc. The cells are subdivided into the groups A, B and C with different functions and phase positions and are distributed diffusely over the area encountered by the beam of light from the light source. The cells of each group are connected together in parallel to generate three electrical signals, one of which provides pilot control for the feed to the light source to stabilize the signals of the other two groups of photoelectric cells.