Basket winding (or basket-weave winding or honeycomb winding or scatter winding) is a winding method for electrical wire in a coil. The winding pattern is used for radio-frequency

electronic component An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are n ...

s with many parallel wires, such as

inductor An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a ...

s and

transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...

s. The winding pattern reduces the amount of wire running in adjacent, parallel turns. The wires in successive layers of a basket wound coil cross each other at large angles, as close to 90 degrees as possible, which reduces energy loss due to electrical cross-coupling between wires at radio frequencies.

Purpose

The basket winding method is used for coils designed for use at

frequencies Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from '' angular frequency''. Frequency is measured in hertz (Hz) which is e ...

of 50 kHz and higher to reduce two undesirable side effects, '' proximity effect'' and '' parasitic capacitance'', that arise in long parallel segments of current-carrying wire. The proximity effect is caused in a wire by the magnetic field from current flowing in nearby parallel wires, such as other loops in the same coil. If two adjacent wires carry a current in the same direction, then the effect is felt in both – the magnetic field of the nearby wires causes current in each wire to be concentrated in a small region on the wire’s surface farthest from the adjacent wires. The concentration of current along a small portion of the conductor increases the wire’s

resistance Resistance may refer to: Arts, entertainment, and media Comics * Either of two similarly named but otherwise unrelated comic book series, both published by Wildstorm: ** ''Resistance'' (comics), based on the video game of the same title ** ''T ...

and hence increases energy loss. At medium and high radio frequencies the increased resistance of the inductor can increase the bandwidth of tuned circuits and reduce the circuit’s frequency selectivity, or

Q factor In physics and engineering, the quality factor or ''Q'' factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is. It is defined as the ratio of the initial energy stored in the resonator to the energy ...

. Parasitic capacitance is the consequence of parallel turns of wire acting as

capacitor A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a ...

plates, storing charge between adjacent wires. The parasitic capacitance can cause the coil to become self-resonant at one or several frequencies, which interferes with the intended tuned resonance and blocks and reflects current at the self-resonant frequency. Unfortunately basket-weave coil winding increases the physical size of the coil, which increases leakage inductance.

Methods

Basket windings are often wound with Litz wire, a thin, multi-strand wire with each strand individually insulated, which further reduces losses. Cotton or fabric insulation is important from a mechanical point of view during the winding process, because a common enameled magnet wire does not provide sufficient surface friction between coil layers to hold the turns at large angles.

External links

Photo and description of basket winding

References

{{reflist Electromagnetic coils

Purpose

Methods

See also

External links

References