There are many different types of transformers that are used in electronic components and applications. The specific type, shape and even windings on the transformer is a factor in choosing one specific option over another.
Some of the most commonly used options are the toroidal transformers. They are easily identified by their shape, which is toroidal in nature and can be small to large. The toroidal shape is often called a donut or a ring and includes a magnetic core of a variety of materials surrounded by the windings.
Less Leakage
The advantage of the specific shape of the toroidal transformers is the ability to reduce the leakage of magnetic flux outside of the transformer. The shape helps to prevent this leakage because of the symmetry. With less EMI (electromagnetic interference), these transformers can be easily used a variety of systems that would be impossible to use traditional square shaped cores that release higher levels of EMI.
In turn, in addition to simply being more compatible with more complex systems, circuits or devices, there is less cost in production as additional shielding is not required for the components. There is also a lower cost as a smaller transformer can often be used in place of a larger size that would be required with another transformer shape.
To meet many of the regulations and standards for EMI required for both domestic and international electronic circuits and devices, the toroidal transformer is the ideal solution.
Improved Performance
With the shape of the toroidal transformers, there is a stronger or higher magnetic field created throughout the center of the core. This translates into higher inductance in addition to lower impedance. The lower impedance is possible due to the short length of the windings compared to the longer windings seen with the elongated types of cores.