XPost: uk.d-i-y, alt.home.repair, alt.sci.physics   
   From: me@privacy.invalid   
      
   "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.   
      
   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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