Toroidal inductors and transformers
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Several small toroidal inductors. The major scale is in inches.
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A small toroidal transformer.
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Toroidal inductors and transformers are a kind of electronic component. They typically consist of a circular, ring-shaped magnetic centre. The magnet is usually considered a monopole, although the central axis will have a dipole, and have the advantage of being wound continuously in a single direction, thus there is no inductive interference between windings as in a solenoid that is wound back and forth.
Toroidal Inductors And Transformers Media
Traditional transformers wound on rectangular-shaped cores.
Interior of a linear power supply with toroidal mains transformer.
Fig. 1. Coordinate system. The Z-axis is the nominal axis of symmetry. The X-axis chosen arbitrarily to line up with the starting point of the winding. ρ is called the radial direction. θ is called the circumferential direction.
Fig. 2. An axially symmetric toroidal inductor with no circumferential current.
Fig. 3. Toroidal inductor with circumferential current
Fig. 4. Circumferential current countered with a return wire. The wire is white and runs between the outer rim of the inductor and the outer portion of the winding.
Fig. 5. Circumferential current countered with a return winding.
Fig. 6. Circumferential current countered with a split return winding.
References
- Griffiths, David (1989), Introduction to Electrodynamics, Prentice-Hall, ISBN 0-13-481367-7
- Halliday; Resnick (1962), Physics, part two, John Wiley & Sons
- Hayt, William (1989), Engineering Electromagnetics (5th ed.), McGraw-Hill, ISBN 0-07-027406-1
- Purcell, Edward M. (1965), Electricity and Magnetism, Berkeley Physics Course, vol. II, McGraw-Hill, ISBN 978-0-07-004859-1
- Reitz, John R.; Milford, Frederick J.; Christy, Robert W. (1993), Foundations of Electromagnetic Theory, Addison-Wesley, ISBN 0-201-52624-7
Other websites
- Approximate inductance of a toroid includes formula, but assumes circular windings
