Abstract: The object of the present invention is the improvement of logarithmic amplifiers and/or converters and the applications of such devices in particular to photometric analyzer apparatuses.These amplifiers are characterized by the fact that they are linear with an amplification gain programmable by the .mu.P computer and that they may be preceded optionally by a reference voltage system.Application to the measurement of light transmitted by samples.

Abstract: A rotor, which has a center and a periphery, of a centrifuge analysis device. The rotor comprises, from the center of the periphery: central receptacles for liquids to be diluted before analysis; calibration vessels and overflow vessels disposed circumferentially adjacent to each other in respect to a circle concentric with the rotor; a mixing vessel communicating with each calibration vessel; and a plurality of measuring cells, each connected to the mixing vessel through a duct. Each calibration vessel is further provided with: a feed orifice through which it comunicates with one of the central receptacles; an exit orifice located in the wall of said calibration vessel opposite the feed orifice and permanently open; and an overflow orifice located at a position between said feed and exit orifices and through which the calibration vessel is connected to one of the overflow vessels.

Abstract: In a device for bringing a liquid sample successively into contact with a number of reagents, contact with the reagents is effected in a series of cells. These cells communicate with one another and are carried by a rotor, transfer of the liquid sample from one cell to another being effected by rotating the rotor. The direction of rotation of the rotor is reversed after each transfer operation. The number of cells constituting the series is at least equal to the number of reagents. The reagents are placed in the cells beforehand.