Toroidal Power Transformer: Working & Advantages

Toroidal transformers get their name from their toroidal (or donut) shape. These transformers have a magnetic core. These are seen as a decided improvement on the earlier square-shaped transformers. The ring-shaped magnetic core is composed of a ferromagnetic material with a wire wound around it. Silicon and steel could also be used in its composition.

Toroidal power transformer manufacturers supply to a very wide range of industries that work with electronic circuits from equipment manufacturers to electronic service suppliers, such as power distribution companies. As one of the most efficient design, these transformers are the preferred option.

How Does It Work?

A transformer is essentially a very simple electrical device that is found in almost all electrical devices. Their essential function is to take an alternative current from one level to another. An alternative current or AC has a particular wave pattern. In a standard AC voltage cycle, the wave starts from zero, reaches a positive peak and then falls to zero at the halfway mark. It will then move to the opposite direction, reaching its peak and then falling back to zero, completing one cycle. In one second there are 60 cycles or 60 Hertz.

In a toroidal transformer, electricity is passed through the coil that is wrapped around the ring-shaped core. As the AC voltage reaches its peak in the positive direction, a positive magnetic field is created, which collapses as the voltage falls to zero. Then as the wave moves to the opposite negative direction, a negative field is created, which again collapses as the cycle is completed.

This collapsing magnetic field passes through a secondary coil, which is also wrapped around the core. This produces the output voltage. The ratio between the number of coils in the primary and the secondary decides the voltage. If it is 1:2, the voltage will be halved. For double the voltage, the ratio must be 2:1.

The Advantages Of A Toroidal Transformer

As mentioned above toroidal power transformer manufacturers today supply to a wide range of industries. This is because this donut-shaped design has many advantages over the earlier square-shaped transformers.

Size: As simple geometry will show you, a circle occupies much smaller space and hence, requires less material to build. The ring shape needs less material than the earlier transformers. The smaller shape means that it is also lighter. The small size has many other advantages, making it easier to mount and more applicable.

Winding distribution: It is always easy to wind a ring around a ring than a square-shaped object. The shape itself means that we can achieve a more regular winding pattern and completely avoid big gaps. The shape also requires less wiring to wind around. This brings down the cost of winding and makes it lighter.

Flexibility: Changing the dimensions of toroidal transformer is actually quite simple. It is simply a matter of modifying the height and diameter, while keeping the cross-section constant. This is easy to achieve with just few alteration. This gives the transformer an incredible flexibility that no other design has.

Easy to mount: As explained above, the toroidal core is light and compact, which makes it naturally easy to mount. But it’s not just the weight. It can be mounted with a single screw where the square shape needs four. In addition, it requires less effort and fewer special instruments.

Efficiency: The toroidal transformer simply has a more efficient design. The ring shape means that it has a closed loop, which means a higher magnetic field that is contained within the core. This means a higher Q factor. The design has an at least 95% efficiency. The shorter windings also ensure a low secondary impedance, which further improves efficiency. The symmetry of the toroid also controls the leakage flux.

Low noise: Toroidal transformer design creates a very low mechanical hum. The windings are tight, closely packed, welded and also have a coating. In other designs the coil turns and the core laminations create a vibration, which results in a rather irritating hum.


Toroidal power transformer manufacturers have emerged as the preferred supplier of transformers. With its efficient and economical design, it can be used across a wide range of industries.

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