5
\$\begingroup\$

Some circuits have parallel bars on their inductor symbols such as:

Enter image description here

Does that mean the inductor is wound around a magnetic core instead of air? Is that how a differential choke is represented?

\$\endgroup\$
5
\$\begingroup\$

Typically yes. The bar is used to indicate some form of ferrous core.

enter image description here

https://www.conceptdraw.com/How-To-Guide/inductors-symbols

| improve this answer | |
\$\endgroup\$
4
\$\begingroup\$

A solid bar indicates a ferrous core (core made of a ferrous metal, such as iron).

A dashed bar indicates a ferrite core.

| improve this answer | |
\$\endgroup\$
  • \$\begingroup\$ ferrous core never heard of it. did you mean fameous? \$\endgroup\$ – cm64 Jan 18 '19 at 20:40
  • \$\begingroup\$ @cm64 What Electron means is a core made of a ferrous metal, such as iron or steel. \$\endgroup\$ – Hearth Jan 18 '19 at 20:41
  • \$\begingroup\$ yes.. iron or steel based core \$\endgroup\$ – Satish Singupuram Jan 18 '19 at 20:42
  • 2
    \$\begingroup\$ yes.. air core colis will have much more less inductance when compared to iron or ferrite core inductors. \$\endgroup\$ – Satish Singupuram Jan 18 '19 at 20:49
  • 2
    \$\begingroup\$ "Ferrous", made of ferrum, chemical symbol Fe, latin for iron. \$\endgroup\$ – Transistor Jan 18 '19 at 20:53
2
\$\begingroup\$

I see this convention for ferrites such as in the filter you show, tho I can't seem to find an official source indicating this is an official standard of some kind.

| improve this answer | |
\$\endgroup\$
1
\$\begingroup\$

Well, IEEE Std 315 specifies this symbol for an inductor with a "magnetic core":

inductor with core, symbol from IEEE Std 315

The standard doesn't show any symbols with a single bar, at least as far as I can see.

| improve this answer | |
\$\endgroup\$
  • \$\begingroup\$ When I was a boy, British laminated FeSi cores had three lines; ferrite cores were a single dashed or sometimes dotted line. \$\endgroup\$ – Michael Harvey Jan 19 '19 at 11:58
  • \$\begingroup\$ @MichaelHarvey Yes, I have also seen many variations over the years. I just wanted to point out that there really is a standard way of drawing these things. \$\endgroup\$ – Elliot Alderson Jan 19 '19 at 12:02

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.