High Frequency Silk Covered Copper Litz Wire for Indutor

Litz wire is very effective below 500 kHz; it is rarely used above 2 MHz as it is much less effective there.

At frequencies above about 1 MHz, the benefits become gradually offset by the effect of parasitic capacitance between the strands. At microwave frequencies, the skin depth is much smaller than the diameter of the strands, and the current that is forced through the inner strands induces strong eddy currents in the outer strands, which negates the benefits of litz wire to the point where it performs much worse than solid wire of the same diameter.

Litz wire has a higher impedance per unit cross-sectional area, but litz wires can be used at thicker cable sizes, hence reducing or maintaining cable impedance at higher frequencies. Construction of litz wires usually involves extremely fine wires often available with a silver plate or solid silver. The individual strands often make use of a low-temperature lacquer coating that typically requires silver-solder-iron temperatures to melt - which is removed when making connections. The bundles of wires can also use silk outer insulation.