A variable capacitor includes a first component made of conductive material in
the form of an at least partially hollow rod, comprising a hole or perforation
extending axially into the body of the first component to form a tube portion,
and a second component also made of conductive material in the form of a rod able
to be fitted to a variable depth into the axial hole, the engagement depth of the
second component in the first component determining the degree of capacitive coupling
between them and therefore the value of the resulting capacitor. The capacitor
tube portion is provided on its internal face, preferably substantially over the
whole depth of the axial hole, with a layer of dielectric material, the latter
extending in a continuous manner over the edge defining the access aperture of
the hole and onto an adjacent part of the external face of the tube portion.
