2 minutes reading time (437 words)

Is There a Difference Between A Donut And Toroidal Current Transformer?

Toroidal current transformers are power transformers containing a toroidal core upon which the secondary and primary coils are wound. These current transformers obtain their name from the donut like shape. The transformer consists of a circular magnetic core around which wires wrapped. They are used in numerous AC electronic circuits. Therefore, there is no difference between a Toroidal and donut transformer, with both terms referring to the same device.

When a current travels through the primary, it precipitates an electromotive force and subsequently occurred in the secondary winding, thereby conveying power from the primary coil to the secondary. A donut current transformer is used commonly when AC current levels that are to be monitored are greater than 75 amperes. This transformer gives added isolation from the conductor. At Midwest Current Transformer, we offer toroidal current transformers (CT) for a wide array of power applications.

Toroidal Current Transformers

Toroidal current transformers are often much more compact than power transformers of the conventional nature with the same ratings. In addition, the enhanced efficiency results in lower temperatures. The toroidal current transformer’s unique shape enables a reduction of winding or resistive losses, shorter coils, and enhanced efficiency. As a result of their construction they do not allow for stray fields that are outwardly radiated. They deliver high resistance to magnetic fields externally imposed.


The compact size of these current transformers makes them the perfect option for applications that involve electronic circuits. Therefore, these current transformers often use in inverters, computers, and many other similar type of devices. These toroidal current transformer models are also quieter – the home less than conventional transformer options, making them ideal for TV, amplifier, and audio system applications.

Toroidal current transformers are highly ideal for use in clinical device and equipment applications in the medical industry. Exceptional efficiency is very important when it comes to medical systems that require reliable and noiseless operation and low current leakage. These transformers are compact and lightweight and can integrate easily into medical equipment and instruments in which there are particular weight limitations and space constraints involved.

To learn about the various toroidal current transformer options we have available at Midwest Current Transformer, and give our team a call today at 800.893.4047 or email This email address is being protected from spambots. You need JavaScript enabled to view it..

Technical Parameters of an Instrument Current Tran...
How Do Toroidal Transformers Work?