Abstract: An arrangement is provided for testing DUTs with a chuck that has a support surface for supporting of a DUT as well as for supplying the support surface with a defined potential, or for connecting the DUT. The arrangement further includes a positioning device for positioning the chuck as well as an electromagnetic shielding housing enclosing at least the chuck. Inside the housing and adjacent to the chuck, a signal preamplifier is arranged whose signal port facing the chuck is electrically connected with the support surface, wherein the signal preamplifier is moveable together with the chuck by the positioning device in a way that it holds its position constant relative to the chuck during positioning. The signal preamplifier is connected to a measurement unit outside of the housing via a measurement cable.

Abstract: A device for rapidly changing objectives with threaded fastening on an optical instrument comprises an instrument adaptor which has, at one end, an external thread corresponding to the external thread of the objective, and, at the other end, a bayonet mount for fixably holding a bayonet base, and an objective adaptor which has, at one end, a bayonet base which can be connected to the bayonet mount of the instrument adaptor, and, at the other end, an internal thread corresponding to the internal thread of the optical instrument.