×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

LED Heat Calculations

LED Heat Calculations

LED Heat Calculations

(OP)
I'm trying to get a good handle on how to estimate the heat created from different LEDs.  Not really sure how better to describe the question but it's kind of hard to design a proper heat transfer system when I don't know what's coming in.  

I've checked around and haven't found much more than calculations on voltage, current and resistors to use.

Thanks in advance.

RE: LED Heat Calculations

If you know the voltage and current, then V times I will be very close to the heat loss in an LED circuit.  The LED requires a resistor somewhere to limit the current.  The heat loss is divided mainly between this resistor and LED itself with most of the loss in the resistor.

 

"Theory is when you know all and nothing works. Practice is when all works and nobody knows why. In this case we have put together theory and practice: nothing works... and nobody knows why! (Albert Einstein)

RE: LED Heat Calculations

If you know the Vf of the LED under the operating conditions, then you can more-exactly calculate the power at the LED (I times Vf = watts).

You could even adjust for the energy emitted as light (as opposed to heat) by reference to the efficiency. Or leave this added margin as an intentionally-overlooked added safety factor.

 

RE: LED Heat Calculations

Quote (VE1BLL):

If you know the Vf of the LED under the operating conditions, then you can more-exactly calculate the power at the LED (I times Vf = watts).

You could even adjust for the energy emitted as light (as opposed to heat) by reference to the efficiency. Or leave this added margin as an intentionally-overlooked added safety factor.
This is the safest method and the one I use, except when projects require very narrow specs.

Dan - Owner
http://www.Hi-TecDesigns.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources