XPost: uk.d-i-y, alt.home.repair, alt.sci.physics   
   From: CFKinsey@military.org.jp   
      
   On Thu, 03 Oct 2019 19:50:02 +0100, NY  wrote:   
      
   > "Commander Kinsey"  wrote in message   
   > news:op.z83kvpd1wdg98l@picard.lan...   
   >> On Thu, 03 Oct 2019 19:29:42 +0100, Robert  wrote:   
   >>   
   >>> On 03/10/2019 14:29, Commander Kinsey wrote:   
   >>>> Why do LEDs generate heat? I want a technical answer not "because   
   >>>> they're inefficient". And will we ever make them more efficient?   
   >>> Besides the inefficiencies in the LED itself which other posters have   
   >>> covered, LED lamps have some current regulation or power supply built-in   
   >>> which will not be 100% efficient and thus generates heat.   
   >>   
   >> True, but it's the LEDs themselves that are the warmest, and also the most   
   >> susceptible to heat.   
   >   
   > But if you feel a Philips Hue bulb which is the size of an old tungsten 100W   
   > bulb, the part that gives off light (presumably where the LEDs are) is cool.   
   > It is the neck, near the fitting, which gets hot - and I presume that's   
   > where the PSU is.   
      
   Or where the heatsink from the LEDs is.   
      
   > Likewise for GU10 bulbs (Philips Hue or ordinary non-dimmable LED) the front   
   > and conical sides don't get hot, whereas the neck near the fitting gets hot.   
      
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