View Single Post
  #82   Report Post  
Posted to uk.d-i-y
Dave W[_2_] Dave W[_2_] is offline
external usenet poster
 
Posts: 923
Default Why do LEDs generate heat?

On Thu, 3 Oct 2019 06:37:34 -0700 (PDT), whisky-dave
wrote:

On Thursday, 3 October 2019 14:29:30 UTC+1, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because they're inefficient".


That is the technical answer just lioke why does a wire get hot when curremnt passes through it.

And will we ever make them more efficient?


Probably.


If you plot voltage across the LED versus current through it, the
curve is not linear like a resistor. At low voltage it hardly
conducts, but at higher voltage it conducts a lot, and the curve
flattens like a not very good zener diode, limiting the voltage.

Voltage times current equals watts i.e. heat plus a little light.
Light has a power but it's miniscule. Complicated physics theory might
explain how the light is produced and why so little of it, but we
lesser mortals wouldn't be able to understand it.
--
Dave W