Abstract: A multichannel bidirectional DC converter includes first and second parallel current channels and a controller. The first channel has a first inductor, first and second switches, and a device operable for detecting a current null passage (zero crossing) of current of the first inductor. The second channel has a second inductor and third and fourth switches. The controller controls the switches to turn on and off such that the channels can be driven in either a boost converter mode or a buck converter mode at a given time. The controller is operable with the device of the first channel for detecting a period of the current null passage of the first inductor. The controller drives the channels with a time delay with respect to one another based on the detected period such that the channels operate in a critical conduction mode.

Abstract: A multichannel bidirectional DC converter includes first and second parallel current channels and a controller. The first channel has a first inductor, first and second switches, and a device operable for detecting a current null passage (zero crossing) of current of the first inductor. The second channel has a second inductor and third and fourth switches. The controller controls the switches to turn on and off such that the channels can be driven in either a boost converter mode or a buck converter mode at a given time. The controller is operable with the device of the first channel for detecting a period of the current null passage of the first inductor. The controller drives the channels with a time delay with respect to one another based on the detected period such that the channels operate in a critical conduction mode.

Abstract: A holder (2) for sample liquid containers, e.g. Eppendorf vessels (15), is horizontally displaceable between a working position above a magnetic arrangement (4) and a heating position above a hotplate (5). The latter are supported on a baseplate (3) which can be vertically displaced by means of a lifting device (9) between a lowered passive position and a raised active position in which the magnetic arrangement (4) and the hotplate (5) act on the sample liquid in the Eppendorf vessels (15) and attract ferromagnetic particles suspended there. To improve the interaction between the ferromagnetic particles and the sample liquid, the magnetic arrangement (4) can be transversely moved by a stepping motor (6) between a first position, in which, for example, a magnetic plate (14) acts on a row of Eppendorf vessels (15) from the right side, and a second position, in which said magnetic plate (14) acts on the same row of Eppendorf vessels (15) from the left side.

Abstract: A sensor device for detecting the degree of wetting of a multi-layer transparent pane, made in particular of glass, by an, in particular, drop-shaped precipitation. The sensor device is provided with a beam guide element which comprises two beam windows and cooperates with a beam transmitter and a beam receiver. In order to prevent spurious beams caused by an extremely thin intermediate layer located in the pane from having a noticeable influence on the signal used to control the windscreen wiper system, the beam guide element comprises a further beam exit window in the central region of its rear surface facing away from the pane. The region is located between the two beam windows. The further beam exit window is allocated to the measuring path and cooperates with an additional beam detector. Only those irrelevant beams reflected at the extremely thin metallic intermediate layer located in the pane exit therefrom.