摘要:
The invention relates to a power supply system (3) intended to supply power to an electrical load (C), the system comprising: two input terminals, namely a negative terminal and a positive terminal, connected to a supply mains (A) delivering an AC voltage; an input capacitor (C1) connected to one of the terminals of the system; a rectifier module (33) for generating a DC voltage on a DC bus from the AC voltage; a bus capacitor (Cb) connected between a positive line (31) and a negative line (32) of the DC bus, and upstream of the input capacitor (C1), two normally-on bidirectional semiconductor transistors (T1, T2) connected in series, fabricated in a wide-bandgap material and able to operate in current-limiting mode.
摘要:
A proximity sensor includes a coil for sensing metal objects which are part of an oscillatory circuit and an oscillator which drives the oscillatory circuit at a constant frequency. A tuning device is connected in parallel with the oscillatory circuit. The tuning device is a variable gain amplifier with feedback via an inductive or capacitive impedance.
摘要:
The invention relates to electronic badges equipping portable objects, such as plastified cards and capable of being identified at a distance by suitable readers in order to ensure operation such as the unlocking of a lock. These badges are of a passive type, that is to say supplied exclusively from the outside by inductive coupling and they are in addition of a type reprogrammable through channels, each comprising an inductive coupling (at the level of inductances) from a suitable apparatus. The circuitry for forming the binary coded identification signals of the badge comprise a dead memory, a life memory or buffer and a rapid reading and writing circuit which provides the connections between these two memories, as well as the connections between the dead memories and the reprogramming channels.
摘要:
This system is provided for the field of electronic facsimile transmitting of a picture and relates more particularly to the compression of data to reduce the number of bits to be transmitted at a given resolution of the picture. Compression is effected by a correlation of neighbouring points of the picture by omitting, at the transmitting end, one point in four on two adjacent lines and by restituting it at the receiving end by means of a relatively simple Boolean function which takes into account the structure of the characters used in that picture. That first compression may be combined with a second compression due to the coding of the length of a white range.
摘要:
An overvoltage protection device, including: an input configured to be connected to a power supply mains; an output configured to be connected to an electronic system to be protected; two bidirectional field-effect semiconductor transistors of normally-on type, connected in series between the input and the output, fabricated in a wide-bandgap material and configured to operate in current-limiting mode; and a resistor connected in parallel with the two transistors.
摘要:
The voltage surge protection device comprises at least one input designed to be connected to an electric power supply system, at least one output designed to be connected to an electric circuit to be protected, and voltage surge limiting means connected between the inputs and outputs to protect said electric circuit against voltage surges able to be applied on the inputs. The voltage surge limiting means comprise bidirectional series electronic limiting means comprising at least two inputs/outputs connected in series with at least one of said inputs, and which are turned on when a low voltage drop occurs when a circulating current is lower than a current limiting value, and limiting said circulating current by increasing a voltage drop between said inputs/outputs.
摘要:
Detector comprising a sensor and a processing circuit connected to a load by means of two wires. Two switches (I1, I2) are arranged in series in a switching circuit leg (21), the ends of which (C, D) are connected to the detector terminals and the middle point (S) to a terminal (F) of the processing circuit. When operating (I1) is conductive and (I2) determines a parallel regulation of the voltage (V) at the processing circuit (12) terminals ; when in rest position, (I1) determines a series regulation of the voltage while (I2) is blocked.
摘要:
A reader identifies coded electronic badges without contact with the latter, by simple inductive coupling of inductances, the electrical supply of the badge being ensured from a voltage at high frequency F generated by the reader. The code of the badge, composed of a sequence of bits following one another at a frequency f very much less than F, is used to modulate a voltage of intermediate frequency fi comprised between f and F and the thus modulated voltage controls an electronic switch adapted to short-circuit a resonant circuit of the badge.