Abstract: A compensated temperature distance detector wherein the detecting coil is realized in the form of wires, divided and isolated the one from the others. A first set of wires (L) constitutes the oscillating coil parallel connected to a capacitor and fed between two distinct voltages (VCC and M) through a current source (IB) and a second set of wires (L'), connected at a first extremity to a first set of wires and to a generator, is connected at its other extremity to a third voltage (V1), whereby a d.c. current flows through the series connection of the first and second sets of wires.

Abstract: A bipolar power switch (4) in series with the primary of an ignition coil (2) and a detection resistor (R1) associated with a voltage divider (R2, R3) supplying a voltage V.sub.D ; a controlled amplifier-comparator (9), the first input of which receives the measured voltage and the second input receives a reference voltage (8), and the output of which is connected with the base of the switch (4), this amplifier-comparator acting for limiting the base current when the measured voltage is approaching the reference voltage; a series resistor (R10) between the output of the amplifier-comparator (9) and the base of the switch (4); and a differential amplifier (11), the inputs of which are connected with the terminals of the series resistor and the output of which is connected with the first input of the amplifier-comparator.

Abstract: The invention relates to an angular measurement device comprising a variable reluctance magnetic circuit comprising a fixed portion (3) associated with a coil (2) and at least a moving element (4) attached to a part (5) rotating in front of the fixed portion, the angular position of which is to be detected, comprising: means (I) for integrating the voltage across the coil, means for measuring the instantaneous value of the integrated voltage (15), means for comparing this measure to a calibrating curve of the integrated voltage versus the angle.

Abstract: The invention provides a frequency-voltage converter having a voltage source; a first capacitor, a second capacitor, a current generator and a sequencer receiving a recurrent signal; said first capacitor being charged to a value Vo after a time To, then discharged by a discharge current Jd proportional to the square of the instantaneous residual voltage in said first capacitor, during a time T-To; the residual charge which is present in the first capacitor after the time T being recopied at the beginning of each recurrence into said second capacitor.

Abstract: Ultrasonic process and apparatus for monitoring and measuring the evolution with time of physico-chemical and biological phenomena. There is plunged into the medium or media (4) to be monitored a bar (3) into which ultrasound (2) is injected in order to collect secondary echoes (F2, F3) due to numerous reflections from the lateral surface of the bar (3) brought into contact with the medium (4), one of the secondary echoes (F2) is selected and the evolution with time of the amplitude of this echo is recorded, this representing the evolution of the medium being monitored, in particular the setting of concrete or the polymerization of a resin.

Abstract: Tris(hydroxymethyl)aminomethane, an intermediate of organic synthesis, in ystalline form is made by formylation followed by hydrogenation. Nitromethane and formaldehyde in a molar ratio on the order of 1:3 are reacted in a concentrated alcohol medium made up of a 2 to 5% mixture of methylene chloride in methanol, in the presence of 1 to 10 milliequivalents per mole of nitromethane of a solid base catalyst selected from sodium or potassium, with agitation for a period between 3 and 36 hours at a temperature below 50.degree. C.

Abstract: A protective device for, and a monolithic integrated transistor formed on a semi-conductor substrate of at least first conductivity type and having a first collector region of opposite conductivity type on the substrate, a buried region of opposite conductivity type and slight resistance between the substrate and collector regions, a base region of the first conductivity type formed on the collector region, an emitter region of the opposite conductivity type formed on the base region, the buried region being connected to the surface at the collector terminal and at a separate terminal. The voltage between the collector and separate terminals is compared with a reference in a differential circuit and a control signal produced to control the base voltage of the integrated transistor, and accordingly to protect the integrated transistor.