Low inter-winding capacitance coil form
A coil form with a low inter-winding capacitance is disclosed including a bobbin formed from an electrically insulating material and including a tube section shaped wall. A coil is mechanically supported by the bobbin and includes a first plurality of conductor windings on the outside of the wall and a second plurality of conductor windings on the inside of the wall. Furthermore, a transformer with such a coil form as any of its primary or secondary windings is disclosed.
1. A coil form, comprising:
a bobbin made of an electrically insulating material and including a tube section shaped wall; and
a coil mechanically supported by the bobbin and including a first plurality of conductor windings on an outside of the tube section shaped wall and a second plurality of conductor windings on an inside of the tube section shaped wall,
wherein the first plurality of conductor windings and the second plurality of conductor windings are formed from a single continuous conductor section that passes the tube section shaped wall at one end of two ends of the bobbin.
2. The coil form of claim 1 , further comprising a third plurality of conductor windings on the outside of the tube section shaped wall, wherein the first plurality of conductor windings, the second plurality of conductor windings and the third plurality of conductor windings are formed from the single continuous conductor section.
3. The coil form of claim 2 , wherein the single continuous conductor section passes the tube section shaped wall at both ends of the bobbin.
4. The coil form of claim 2 , wherein the first plurality of conductor windings and the third plurality of conductor windings are separated by a flange of the bobbin radially extending from the outside of the tube section shaped wall.
5. The coil form of claim 4 , further comprising connection leads for electrically connecting both ends of the coil, wherein the connection leads are connected to the ends of the first and third pluralities of conductor windings on opposite sides of the flange of the bobbin.
6. The coil form of claim 5 , wherein the connection leads are extending through separate channels of an insulating housing mechanically connected to the bobbin.
7. The coil form of claim 1 , wherein the bobbin comprises an end flange radially extending from the outside of the tube section shaped wall at at least one of its ends, the end flange comprising a port through which the single continuous conductor section passes.
8. The coil form of claim 1 , wherein the second plurality of conductor windings comprises one layer of conductor windings on the inside of the tube section shaped wall only.
9. The coil form of claim 1 , wherein each plurality of conductor windings on the outside of the tube section shaped wall comprises one layer of conductor windings on the outside of the tube section shaped wall only.
10. A transformer comprising the coil form of claim 1 as any one of its primary or secondary windings.
11. The transformer of claim 10 , wherein the other of the primary or secondary windings comprises a further coil of a plurality of conductor windings wound on the outside of a first tube section shaped wall of a further bobbin made of an electrically insulating material, wherein the further bobbin comprises a second tube section shaped wall enclosed by the first tube section shaped wall and supporting the coil form within the further coil.
12. The transformer of claim 11 , wherein a gap remaining between the coil form and the first tube section shaped wall of the further bobbin is filled with a potting material.
13. The transformer of claim 12 , wherein the potting material encloses the primary and secondary windings within a transformer housing.
14. The transformer of claim 11 , wherein the second tube section shaped wall has a circular, oval, ellipsoidal, or rectangular cross-sectional profile.
15. The coil form of claim 4 , wherein except for both ends of the single continuous conductor section, a winding layout of the coil form is mirror-symmetric with regard to a symmetry plane extending through the flange.