How do Toroids work, and What are they used for?

They're used for lots of things: washers, bangles, rings on fingers; it's just a shape, like 'square' is.

 

Are you thinking of toroidal magnets?

 

A toroidal ferrite core with wire wound on it is called a choke in EE.
Try wikipedia (and an old PC power supply); do you understand induction?

 

Hmm, well, choke coils are fairly ubiquitous, see what a choke does and see if it looks useful.

 

An inductor blocks transmission of a fast changing signal such as external interference on a wire.
They are normally only called chokes when they are inductors in circuit.

 

It depends on the application, and frequency domain where the material can be powdered iron, or wound soft steel tape, or ferrite.

In small, bead form, on a wire, torroids block noise. Toroidal cores are even used in 60Hz transformers where a low profile is a requirement. Current transformers, antenna balums, and line filters are some uses. Way back when, square BH core material toroids were used to store data bits (core memory).

Packaged with a couple capacitors, or used discretely, they are commonly used as line filters.