I got this components:

enter image description here enter image description here

Resistance about 9 to 10 Ohms. I am unable to identify this components.

Thank you so much answering this question. Yes it is a 0.15A PTC fuse. ITrip is about 0.5A and it is very slow.

  • 4
    \$\begingroup\$ They are probably self resetting fuses. Being so thick and resistive makes think of some high voltage low current parts. \$\endgroup\$
    – carloc
    Commented Sep 17, 2017 at 12:53

2 Answers 2


I believe they are Tyco/Raychem TRF600-150, high-voltage resettable fuses, rated for 250VDC nominal (600VAC interrupt rating) and 150mA nominal.

I found a Tyco/Raychem datasheet that seems to match general part package and specs. Excerpt from page 10 (note the minimum resistance of 6Ω in the datasheet, which matches your measurement):

excerpt from datasheet

Raychem went defunct in 1999, and were acquired by Tyco, so maybe they are now available under that brand name. If you search Ebay for "Raychem 600 150", you'll find various listings for parts that look exactly like yours.

One example, from this listing, claiming to sell "RAYCHEM PTC Resettable Fuse Radial Leads .16A/.32A 250V 3A NEW 5/PKG":

Raychem polyswitches from Ebay

The bottom row on these says XS1G rather than your WN1U. This is probably a production series code, which differs from batch to batch.

Here is another listing, claiming to sell "( 25 PC. ) RAYCHEM/TYCO PTC TR600-150-2 RESETTABLE POLYSWITCH CIRCUIT PROTECTOR":

Raychem polyswitches from Ebay

  • \$\begingroup\$ They look unbelievably like caramels with wires in in your pictures o.o \$\endgroup\$
    – Weaver
    Commented Sep 17, 2017 at 23:56
  • \$\begingroup\$ Thank you so much answering this question. Yes it is a 0.15A PTC fuse. ITrip is about 0.5A and it is very slow. \$\endgroup\$
    – WalterH
    Commented Jun 1, 2018 at 5:04

It's a 0.15A, 60VDC (600VAC interrupt rating) resettable PTC fuse.

An equivalent is here:




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