摘要 |
<p>A circulator comprises a housing (10) in two halves (12, 11) with a ferrite (18) and associated magnet (16) in a central portion of a first one of the halves (12), the second housing-half (11) above the ferrite having a membrane (32) which is deformable by operation of an adjusting means (33) upon the membrane, so as to adjust the size of an airgap (26) between the membrane and the ferrite. The membrane is preferably the residual portion of the second housing-half following a milling operation to provide a recess (31), the recess accommodating the adjusting means in the form of, e.g., a screw. To further enhance predictability of the performance characteristics of the circulator, the ferrite is seated in a hollow (36) formed in the first housing-half and the securing of the ferrite to the first housing-half is by way of an adhesive applied between a lateral face (37) of the ferrite and a corresponding lateral face of the hollow. <IMAGE></p> |