How does a toroidal choke differ from an ordinary inductor? How do I
use the rating to determine what frequencies it passes and what it
filters out? Is there a good reference for this? A SAMS manual or
something? I couldn't find much on the web.

As a related issue, why are toroidal chokes common in cheap (but
decent) surge suppressors, but the real fancy ones seem to include
very large inductors.

Thanks.

<grizdog@gmail.com> wrote in message
news:1187473624.397931.39660@i13g2000prf.googlegroups.com...
> How does a toroidal choke differ from an ordinary inductor? How do I
> use the rating to determine what frequencies it passes and what it
> filters out? Is there a good reference for this? A SAMS manual or
> something? I couldn't find much on the web.
>
> As a related issue, why are toroidal chokes common in cheap (but
> decent) surge suppressors, but the real fancy ones seem to include
> very large inductors.

A choke is a choke. It is an inductor.

Torroids tend to be more compact and tend to not emit external fields.

No magic ... they are inductors.

The torroid core is a big issue ... and that is a book unto itself.

Inductive reactance is 2*pi*f*L. One often chooses a choke with 10 times
the inductive reactance (compared to the load resistance). That's just a
low-level intro into this topic.

Google for low-pass filters.

"grizdog@gmail.com" wrote:

> How does a toroidal choke differ from an ordinary inductor?

It tends to have less stray field.

It difficult to make gapped cores with toroids though. Instead they tend to made
with a variety of permeabilites.

Graham

<grizdog@gmail.com
>
>
> As a related issue, why are toroidal chokes common in cheap (but
> decent) surge suppressors, but the real fancy ones seem to include
> very large inductors.


** The toroidal chokes seen in most line filters only reduce radio frequency
energy travelling down the wires.

Larger chokes ( likely made with gapped iron cores) will reduce much lower
frequencies, down into the audio band for use with hi-fi systems.



....... Phil