In Episode 7 of No Dumb Questions, we explain the skin effect in alternating current (AC) and why it matters for high-frequency electrical applications.
When AC flows through a conductor, especially at higher frequencies, the current doesn’t spread evenly through the entire cross-section. Instead, it concentrates near the surface of the wire. This reduces the effective area available for current flow, which increases resistance and causes more energy loss as heat.
To address this problem, we introduce Litz wire, which is made of many thin, individually insulated strands twisted or braided together. Because each strand is very small—smaller than the skin depth—and equally shares the current, the skin effect is minimized, allowing current to flow more uniformly through the overall cable.
The result is lower AC resistance, improved efficiency, and reduced power loss—making Litz wire especially useful in high-frequency devices like transformers, inductors, and motors.
Key Technical Takeaways
- Definition: Skin effect is the tendency of high-frequency alternating current (AC) to flow near the surface of a conductor rather than uniformly across its cross-section.
- Impact on Resistance: Shrinks the effective cross-sectional area of the conductor, increasing AC resistance and generating wasted thermal loss.
- Frequency Dependence: Higher operating frequencies yield thinner skin depths, compounding resistance losses in solid conductors.
- Litz Wire Solution: Bundles individually insulated strands smaller than the skin depth, forcing uniform current distribution and drastically lowering AC resistance.
- Typical Applications: High-frequency transformers, inductors, wireless power transfer, and electric motors.
Want to learn more about Litz wire? Visit our website litzwire.com to learn more.
If you liked this one, try Episode 8: What is proximity effect?
Episode 7 Transcript – What is Skin Effect?
Welcome to No Dumb Questions
Welcome to another episode of No Dumb Questions, where the only dumb question is the one you don’t ask.
Today we’re here to talk about skin effect and why it’s important in choosing a Litz cable.
What is the Skin Effect?
When alternating current or AC flows through a conductor, something interesting happens, especially at high frequencies. Instead of the current spreading evenly across the wire’s cross-section, it tends to concentrate near the surface of the conductor. This is called the skin effect. The higher the frequency, the more pronounced it becomes.
Why does it matter? Well, when the current is forced to flow only on the surface, the effective area of the conductor shrinks and the resistance increases. That means more energy is wasted as heat, which isn’t exactly ideal for efficiency.
How Litz Wire Overcomes Skin Effect
This is where Litz wire comes to the rescue. Litz cables are made of many thin, individually insulated strands, twisted or braided together. Each strand is small enough that the skin effect doesn’t limit current flow to just the surface. Plus, the unique weaving ensures all the strands share the current more evenly.
The result? Lower AC resistance, reduced power loss, and better performance in high frequency applications like transformers, inductors, and motors. So whenever efficiency at high frequencies is a priority, Litz cables are the go-to solution for minimizing the impact of skin effect.
Thank you for joining me on No Dumb Questions. If you have any more questions, please feel free to contact us.