1
\$\begingroup\$

The title of this listing says 3W:

http://www.ebay.com/itm/50PCS-3W-RED-80lm-640nm-LED-Plant-Glow-Light-Emitter-with-20mm-star-base-/221518318191?pt=LH_DefaultDomain_0&hash=item3393854a6f

But the specs that follow show a forward voltage (max) of 2.4V and forward current of 700mA. Wouldn't the power in this case be 2.4V * 0.7A = 1.68W and not 3W?

\$\endgroup\$
7
  • \$\begingroup\$ Seems more like a question that is related to marketing rather than electronics design. Is there some way you could re-word this so that there is some sort of technical implication of designing for 1.68W instead of 3W? \$\endgroup\$
    – Funkyguy
    Commented Aug 18, 2014 at 18:52
  • 2
    \$\begingroup\$ Do you have a datasheet? It's likely max pulse power at 10% duty cycle or something similar. \$\endgroup\$
    – ACD
    Commented Aug 18, 2014 at 18:53
  • 1
    \$\begingroup\$ I always ask questions of the seller if they advertise anything that way... \$\endgroup\$ Commented Aug 18, 2014 at 18:55
  • 6
    \$\begingroup\$ Don't buy anything that doesn't have a proper pdf data sheet is my policy. \$\endgroup\$
    – Andy aka
    Commented Aug 18, 2014 at 19:30
  • \$\begingroup\$ The only information I have is from the ebay listing itself. I just wanted to make sure that I wasn't missing something about how I was doing my calculation, since my result was not 3W. \$\endgroup\$ Commented Aug 18, 2014 at 19:33

1 Answer 1

1
\$\begingroup\$

It is most likely the maximum TDP (Thermal Design Power) of the LED, given the substrate/heatsink the actual diode is mounted to.

You should probably contact the seller though, since they might have just screwed up.

\$\endgroup\$

Your Answer

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

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