Abstract: A device for obtaining a control signal corresponding to the density of the fibre covering lying on a fibre carrying element such as the cylinder, the licker-in, the take-off roller, or the doffer of a card. The device includes a holder which extends over the width of the fibre carrying element to span the width of the fibre covering on the fibre carrying element. This holder contains means responsive to the density of the fibre covering which produces electric output signals corresponding to the density of the fibre covering.

Abstract: A method of, and apparatus for, measuring the moisture content of flat textile structures, especially textile webs, wherein the test material is guided over at least one grounded ground-electrode and at least one further electrode is applied to the test material at the side opposite such ground-electrode. The surface of the further electrode is divided into positive, grounded and negative regions.

Abstract: A method of, and apparatus for, measuring the moisture content or dampness of flat structures, especially textile webs, wherein the flat structure has electrical charges withdrawn therefrom prior to initiating the measuring operation.

Abstract: A method of, and apparatus for, measuring the moisture content of flat textile structures, especially textile webs, wherein there are produced, by virtue of the measuring operation, useful signal components of the same polarity dependent upon the conductance of the test material. There are produced disturbance signal components of opposite polarity dependent upon external voltages. And the useful signal components are additively processed into a measurement value, whereas the disturbance signal components, by addition thereof, due to their opposite polarity, at least approximately eliminate one another.

Abstract: A method and apparatus for determining the moisture content of different kinds of materials wherein electrodes having a voltage supplied thereto are applied to the material to be tested for providing a measuring current corresponding to the moisture content of the material. The measuring current is applied to an amplifier having a low-valued input resistance and the moisture content is determined by adjusting a scale graduated in moisture values in accordance with the output of the amplifier. A balancing device is provided for balancing the output of the amplifier and the scale is connected to the balancing device to indicate a balance position as the moisture content value. The amplifier is also provided with a device for converting the measuring current to a voltage corresponding to the logarithm of change in current and a device for providing temperature compensation.