I can't for the life of me, figure out what these diagonal rectangles are...

a busy cat


  • 6
    \$\begingroup\$ FB = Ferrite beads? \$\endgroup\$
    – Dan Laks
    Oct 27, 2014 at 18:53
  • 1
    \$\begingroup\$ yeah, Ferrite Bead with 2A ratings. \$\endgroup\$
    – KyranF
    Oct 27, 2014 at 19:20
  • \$\begingroup\$ Are you referring to FB10 & FB12 or to J6 which is probably some sort of edge connector. Where did you find the image? \$\endgroup\$
    – jippie
    Oct 27, 2014 at 19:30
  • 1
    \$\begingroup\$ @jippie J6 is almost certainly a typical pin and barrel power connector, with an optional switched contact on the barrel that has been shorted and ignored in this application. \$\endgroup\$
    – RBerteig
    Oct 27, 2014 at 23:35
  • \$\begingroup\$ possible duplicate of Meaning of FB symbol in schematics? \$\endgroup\$
    – Makyen
    Dec 15, 2014 at 6:46

1 Answer 1


Those are ferrite beads, rated at 50 \$\text{m}\Omega\$ DC resistance and 2A. At low frequencies, they are predominantly inductive, but become more resistive (lossy) at high frequencies. They are very useful tools for electromagnetic compatibility. They come in surface mount packages, like what is most likely intended for that schematic, as well as clamp-ons for cables.

  • \$\begingroup\$ Rated for 2A and with a resistance of 0.05 ohm. \$\endgroup\$ Oct 27, 2014 at 18:54
  • \$\begingroup\$ That's 0.05Ω at DC (0Hz). \$\endgroup\$
    – Majenko
    Oct 27, 2014 at 19:01
  • 3
    \$\begingroup\$ The symbol is probably supposed to look like the edge view of a toroidal ferrite core with a wire threaded through it. \$\endgroup\$ Oct 27, 2014 at 19:26

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