GB805135A - Improvements in or relating to temperature sensitive reactance devices - Google Patents

Abstract

805,135. Capacitors. MARCONI'S WIRELESS TELEGRAPH CO. Ltd. Sept. 7, 1956 [Jan. 26, 1956], No. 2608/56. Class 37. A temperature sensitive reactance device comprises a first member 4; a plurality of second members 5 each of which, in conjunction with the first member, constitutes a reactance of value dependent upon the spacing between itself and the first member; means 3 operable at will for moving the first member to bring it adjacent any desired one of the second members ; and temperature responsive means for moving the first member relative to the desired one of the second members independently of any movement produced by the operable means 3. As described, a variable capacitor comprises stator plates 1 fixed to spindles 9 at one end of which a steel plate 8 is mounted, and rotor plates 2 mounted upon a driving spindle 3 upon which is also fixed a bi-metallic strip 4. The plate 8 carries a plurality of individually axially adjustable electrodes 5. The bi-metallic strip is shaped as shown in Fig. 2 so that, for every setting, it covers the equivalent of two of the adjustable electrodes 5. The capacitance between the bi-metallic strip 4 and the adjacent electrodes 5 varies with temperature, the bimetallic nature of the strip 4 causing it to approach or recede from the electrodes 5 as the temperature changes, and this variation is used to compensate for the temperature-capacitance variation of the main capacitor. Different settings of the main capacitor requires different degrees of compensation and these are provided by suitably adjusting the individual axial positions of the electrodes 5.