I'm analyzing a circuit (USB game console.)

Three identical ferrite beads (805 or 603 package) are used in the circuit.

It was working but I tried something on circuit. Now it is not working.

I measured the ferrite beads, they are short circuit. I did not measur to ferrite beads when it was working.

Could this be the reason why it is not working?

  • \$\begingroup\$ What did you try on the circuit that caused it but to work? \$\endgroup\$
    – Ron Beyer
    Jan 8 at 19:03
  • \$\begingroup\$ I disassembled and assembly the mcu @RonBeyer \$\endgroup\$ Jan 8 at 19:06
  • \$\begingroup\$ Microwave or RF beads have conductive Zn. HF or LF beads do not and are more insulative. \$\endgroup\$ Jan 8 at 19:09
  • \$\begingroup\$ What are you using to measure these parts? How low of a resistance can it accurately measure? And what values are you measuring? \$\endgroup\$
    – The Photon
    Jan 8 at 19:16
  • \$\begingroup\$ More likely than not you have a solder bridge that's hard to see, use a loupe or a magnifying glass to examine your solder pads. \$\endgroup\$
    – Ron Beyer
    Jan 8 at 19:36

Ferrite beads are meant to have very low resistance at DC, typically less than 5 ohms, and often less than 1 ohm.

If they fail, they tend to fail open-circuit (high resistance) rather than short-circuit (low resistance).


That is normal and so it is not the reason for the circuit not to work.

SMD ferrite beads used in circuits you are measuring are supposed to be almost short circuits for DC currents, about 0.05 ohms.

  • \$\begingroup\$ I guess my multimeter isn't that precise. @Justme so i will check to mcu and connections \$\endgroup\$ Jan 8 at 19:43

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.