GB500428A - Improvements in or relating to electric condensers - Google Patents

Abstract

500,428. Condensers. COX, H. W. July 5, 1937, No. 18619. [Class 37] A condenser comprises a rod or tubular electrode 4 passing through a sleeve 6 of insulating material, and an outer tubular electrode 3 mounted on one end of the sleeve 6, this sleeve being formed of a material having a coefficient of linear expansion higher than that of the electrode 4 so that the capacity between the electrodes decreases with increase of temperature. Alternatively the sleeve 6 may be of conducting material, in which case insulating strips are provided for insulating the electrodes from each other. The inner electrode 4 is slidable in a support 1, bifurcated at its outer end, and can be clamped in adjusted position by a nut 13. The support 1 is provided with an abutment 12 and nut 11, for securing the condenser to a support such as the chassis of a radio receiver. The outer electrode 3 and the support 1 carrying the inner electrode 4, are secured to opposite ends of the insulating sleeve 6 by metal caps 7 which may be formed by assembling the parts in a mould and pouring in molten metal. The rod 4 may be screwthreaded into the support 1 for adjustment. The outer end of the electrode 4 carries an insulating washer 9 to prevent contact with the outer electrode 3. The open end of the electrode 3 may be provided with a cap to exclude dust. In an alternative construction the insulating sleeve 6 extends beyond the inner electrode 4 and is metallized at its end to form the outer electrode. The inner electrode may be formed of metallized ceramic material or a material having a low or negative coefficient of linear expansion. The outer electrode 3 may have a higher coefficient of expansion than the inner electrode 1.