Abstract: Pipette having an axially relocatable control button, a pressure sensor, which is integrated into the control button, a lifting rod, coupled with the control button and having a stopping bead, a hollow driving spindle, accommodating the lifting rod and being axially relocatable, a twisting lock, preventing the driving spindle from being twisted, a turnable driving nut having screw thread engagement with the driving spindle, an axial support of the driving nut, an electric driving motor with a motor shaft, a gear between the motor shaft and the driving nut, an electric power supply, an electric control system, connected to the pressure sensor, the electric driving motor and the electric power supply, which provides an electric voltage to the electric driving motor upon a push on the control button which is indicated by the pressure sensor, so that the motor relocates the driving spindle via the gear in the direction of a relocation of the control button by the push, the driving spindle taking the lifting rod a

Abstract: A proportioning device, comprising a manually operable actuating device, a sensor associated with the actuating device for detecting a force manually exerted on the actuating device, an electric driving motor, an electric control connected to the sensor and electric driving motor for controlling the driving motor during the detection by the sensor of a force exerted on the actuating device, an electric voltage supply connected to the sensor, electric driving motor, and electronic control, and a displacement device coupled to the actuating device and electric driving motor for proportioning a liquid.

Abstract: Pipette having an axially relocatable control button, a pressure sensor, which is integrated into the control button, a lifting rod, coupled with the control button and having a stopping bead, a hollow driving spindle, accommodating the lifting rod and being axially relocatable, a twisting lock, preventing the driving spindle from being twisted, a turnable driving nut having screw thread engagement with the driving spindle, an axial support of the driving nut, an electric driving motor with a motor shaft, a gear between the motor shaft and the driving nut, an electric power supply, an electric control system, connected to the pressure sensor, the electric driving motor and the electric power supply, which provides an electric voltage to the electric driving motor upon a push on the control button which is indicated by the pressure sensor, so that the motor relocates the driving spindle via the gear in the direction of a relocation of the control button by the push, the driving spindle taking the lifting rod a

Abstract: Electronic pipette with a displacement device, an electric drive motor with a drive shaft, a gear mechanism coupled on the one hand to the displacement device and on the other hand to the drive shaft, a magnetic disc rotationally coupled to the drive shaft with at least one magnetic pole on the circumference, at least one magnetic sensor aligned with the circumference of the magnetic disc, at least one additional magnet aligned with the circumference of the magnetic disc, an electronic control device electrically connected to the electric drive motor and the magnetic sensor and an electric voltage supply connected to the electronic control device.

Abstract: A proportioning device, comprising a manually operable actuating device, a sensor associated with the actuating device for detecting a force manually exerted on the actuating device, an electric driving motor, an electric control connected to the sensor and electric driving motor for controlling the driving motor during the detection by the sensor of a force exerted on the actuating device, an electric voltage supply connected to the sensor, electric driving motor, and electronic control, and a displacement device coupled to the actuating device and electric driving motor for proportioning a liquid.

Abstract: A method for the electropermeation of living cells between at least two electrodes over a predetermined interval with an electrical potential or a current, characterised by the following features:a voltage or current source which is not exhaustable over the interval is applied to the electrodes via a controllable power semiconductor functioning as a regulator;the course of the potential or of the current during the interval is predetermined by a setting value transducer which generates any selectable course of curve, and is inputted to a controller which is connected in front of the driver step for the power semiconductor;the controller receives a value, as an instantaneous value, corresponding to the actual potential or current applied at the electrodes;the interval has a time range of a few 100 ns to several minutes.