I'd like to use an old laptop AC adapter in conjunction with an adjustable buck module as a project power supply.

It works, but I'm ignorant of some safety details; for example I'm uncertain whether my adapter, which uses a non-earthed input, is "isolated from the mains".

I've tried researching the symbols on the label, but one symbol which feels relevant I cannot identify:

What is that letter T in a triangle?

Does it mean "safe"?

Or "death"...?

  • 6
    \$\begingroup\$ People use that for charging laptops and have survived. Thus it must be isolated. I do love the exclamation mark, as if it says "Warning: Made in China". \$\endgroup\$
    – Justme
    Jul 16, 2020 at 22:37
  • 1
    \$\begingroup\$ I've scoured the internet trying to figure out this symbol, including reverse image searches. The best theory I have is that it's something proprietary to Astec (now Artesyn, a subsidiary of Emerson). I don't believe it is a symbol related to compliance or safety. \$\endgroup\$
    – JYelton
    Jul 16, 2020 at 23:06
  • \$\begingroup\$ You're joking right? What would you expect from a Dell approved source? and you aren't concerned about the Made In China Symbol /!\ \$\endgroup\$ Jul 16, 2020 at 23:30
  • \$\begingroup\$ it could be a stylized battery symbol \$\endgroup\$
    – jsotola
    Jul 17, 2020 at 0:01
  • \$\begingroup\$ @Justme Thanks for the reassurance. \$\endgroup\$
    – Boann
    Jul 17, 2020 at 10:45

1 Answer 1


Older symbol for Japan's Product Safety Electrical Appliance & Material. Replace by the second symbol.

enter image description here

From Product Approval Markings

  • 1
    \$\begingroup\$ WTG ssrat...... \$\endgroup\$ Jul 17, 2020 at 9:51
  • \$\begingroup\$ So the symbol is not as specifically relevant as I thought. But nice find, thank you. \$\endgroup\$
    – Boann
    Jul 17, 2020 at 10:49

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