Transformers can exhibit higher efficiency at higher frequencies due to reduced core losses and improved magnetic properties of the transformer materials. The efficiency improvement at higher frequencies is primarily attributed to two main factors: reduced core losses and the potential for smaller, lighter transformers.

**Reduced Core Losses:**Core losses in transformers include hysteresis and eddy current losses. At higher frequencies, the core losses decrease because the magnetization and demagnetization cycles occur more rapidly. This results in less time for the magnetic domains in the core material to undergo hysteresis, reducing hysteresis losses. Additionally, eddy currents have less time to circulate within the core at higher frequencies, further minimizing eddy current losses. As a result, the overall core losses are lower, contributing to higher efficiency.**Smaller Core Size:**At higher frequencies, transformers can operate with smaller core sizes while still providing the same power transfer capability. The smaller core size reduces the volume and mass of the transformer, making it more compact and lightweight. This is particularly advantageous in applications where size and weight constraints are critical, such as in high-frequency electronic devices and communication equipment.

It’s important to note that while higher frequencies can enhance transformer efficiency, the choice of frequency involves trade-offs. Higher frequencies may introduce challenges related to increased skin and proximity effects, which can lead to higher copper losses. Therefore, the selection of an optimal frequency depends on the specific application requirements and the balance between core losses and copper losses.