The invention relates to a passive electric structural element with an adjustable capacitance value, commonly called a trimming capacitor.
Adjustable capacitors are usually composed of a stator with a sector-shaped ring electrode covering the surface at an angle of about 180°. The connection of the electrode to the armature produced by a soldering connection lies in a depression.
The rotor is composed of high-grade capacitor ceramic and also has a sector-formed ring electrode which is in contact with the rotor shaft through a soldering connection. The stator and rotor are adjusted to each other through the rotor shaft. It is possible to turn the capacitor layers towards each other at the same time by turning the two structural elements in such a way that the capacitance value of the structural element can be set between an upper and a lower limiting value.
Silver is preferred as a manufacturing material for the electrodes, which is affixed through spraying, screen printing or ram pressing, followed by annealing. The electrodes and especially the stator electrodes as in normal ceramic capacitors, must have high electrical conductivity in order to fulfill the required electrical parameters, especially those regarding small angle losses.