Litz wire is essential for high-frequency applications where skin and proximity effects cause excessive losses in solid conductors. But picking the right one can be tricky. Here’s a simple guide.

1. Know your operating frequency

Frequency is the starting point. Lower frequencies (10–50 kHz) work well with thicker individual strands (e.g., 0.1 mm). As frequency rises (50–200 kHz), conductor diameter must shrink – often down to 0.05 mm or less. A good rule: conductor diameter should be roughly equal to one skin depth at your frequency.

2. Choose the right strand count and bundle size

More strands reduce AC resistance but increase build diameter. For moderate currents, 50–150 strands are common. High-current coils may need hundreds. The total cross-section must handle your RMS current without overheating.

3. Pick the enamel type

Polyurethane enamel is popular because it eliminates stripping, it's solderable type– just direct solder. For higher temperature or aggressive environments, consider polyester or polyimide, but they're non solder type, they require chemical stripping.

4. Consider the outer wrapping

Litz wire often has a nylon, Dacron or silk yarn wrap. This protects the bundle, adds insulation between turns, and makes winding easier. For tightly packed coils or frequent handling, an outer wrap is strongly recommended.

5. Match to your application

RF transformers and wireless charging → fine strands + polyester/nylon cover.

Induction heaters → larger litz bundles with high-temperature insulation.

Medical or audio coils → consistent geometry and solderable polyurethane.

Finally, don’t guess. Use litz wire calculator tools, request sample spools, and test under actual operating conditions. The right litz wire reduces losses, simplifies assembly, and makes your high-frequency design reliable.