HF radios typically use toroidal transformers and winding them is a ceremony of passage for a lot of RF hackers. [David Casler, KE0OG] acquired a query about how they work and answered it in a current video you can see beneath.

Understanding how a traditional transformer works in all fairness easy, however toroids typically appear mysterious as a result of the factor that makes them useful can also be what makes them complicated. The magnetic discipline for such a transformer is sort of completely contained in the “doughnut,” which implies there may be little interplay with the remainder of the circuit, and the transformer could be very environment friendly.

The toroid itself is product of particular materials. They’re often fashioned from powdered iron oxide blended with different metals comparable to cobalt, copper, nickel, manganese, and zinc certain with some type of non-conducting binder like an epoxy. Ferrite cores have comparatively low permeability, low saturation flux density, and low Curie temperature. The powder additionally reduces the era of eddy currents, a supply of loss in transformers. Their largest benefit is their excessive electrical resistivity, which helps scale back the era of eddy currents.

In the event you haven’t labored via how these frequent little transformers work, [David]’s speak ought to show you how to get a grip on them. These aren’t only for RF. You typically see them in energy provides that should be environment friendly, too. In case you are too lazy to wind your personal, there’s all the time assist.