PCB Just out of curiosity I am trying to find out. What type of component is the green flat one in the picture?


1 Answer 1


It is a Polyfuse- a kind of self-resetting current limiting device. There are a few different names for them. Here is a datasheet.

enter image description here

As far as names go, here is Wikipedia's take on it:

These devices are sold by different companies under various trademarks, including PolySwitch (TE Connectivity), Semifuse (ATC Semitec), "Fuzetec" (Fuzetec Technology), Polyfuse (Littelfuse) and Multifuse (Bourns, Inc.).[4] PolySwitch is the earliest product of this type, having been invented at Raychem Corporation (now TE Connectivity) and introduced in the early 1980s. Due to common availability, electronics engineers and technicians often refer to this device as a "polyswitch", in the generic sense, regardless of actual brand.

  • \$\begingroup\$ Awesome. Thanks a bunch. I suppose it is the same one that you can find on many arduino boards? \$\endgroup\$
    – Christian
    Jun 16, 2015 at 19:09
  • \$\begingroup\$ They are available with many (thousands) of different ratings and other specifications, so maybe not exactly the same. \$\endgroup\$ Jun 16, 2015 at 19:10
  • \$\begingroup\$ I see, it is a PTC. I know what that is. ;) And it makes sense, of cause. \$\endgroup\$
    – Christian
    Jun 16, 2015 at 19:21
  • \$\begingroup\$ I've never liked PTC since they don't really have a Temperature Coefficient like the NTC Steinhart-Hart equation but most of the other names (like Polyfuse) are trade names, so I suppose it will have to do. \$\endgroup\$ Jun 16, 2015 at 19:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

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