Abstract: An exemplary condenser microphone includes a printed circuit board, a first via, a second via, and a number of through holes. The first and second vias are formed in the printed circuit board for the signal line and ground line respectively passing therethrough. The through holes are formed surrounding the first and second vias. Inner walls of the through holes are coated with a conductive material.

Abstract: Production of plasterboard includes spreading of a mixture formed of gyps fibers and water onto a continuously moving belt to form a spread layer subsequently precompressed to 110% to 180% of a final board thickness and successively wetted from both sides and thereafter compressing the wetted layer to the final board thickness.

Abstract: An installation for the production of sheet-like members from a mixture of plaster and fibrous material comprises, in addition to a device which prepares the raw materials and mixes them in the dry state in a desired ratio, as well as a device, which adds and mixes in an accurately dosed quantity of water, a spreading device, which spreads a mat of material on a forming line. The mat of spread-out material is compacted in a continuously operating belt press. The latter comprises in known manner two endless steel belts, which are guided around two movable press plates of the belt press, which are spaced apart. The mat of spread-out material is compacted between the forming line, on which it rests, and an endless-belt screen, which bears on the upper steel belt of the belt press and thus acquires a side marked by the endless-belt screen. After being cut up by a cutting device, the individual sheets are turned through 180.degree.

Abstract: A method and apparatus for custom making paper comprising a filter like carrier substrate which is moved sequentially past a series of stations including a station wherein a liquid bearing solids in suspension is passed through the filter like carrier such that the solids form a paper sheet on the substrate carrier, moving the carrier with the deposited solids to a second stage where pressure is applied to the sheet to consolidate the solids into a sheet, further moving the carrier to a third station and exposing the sheet to heat for drying the sheet, finally moving the carrier to a fourth station and removing the so formed sheet from the carrier.