XPost: uk.rec.driving   
   From: a@b.com   
      
   "Major Scott"  wrote in message   
   news:op.wv17zex82eh2io@red.lan...   
   > On Wed, 24 Apr 2013 08:33:48 +0100, Daniel47@teranews.com   
   >  wrote:   
   >   
   >> Major Scott wrote:   
   >>> On Tue, 23 Apr 2013 16:58:35 +0100, Dave Plowman    
   >>> wrote:   
   >>>   
   >>>> In article ,   
   >>>>    Major Scott  wrote:   
   >>>>> > Pulsing an LED is a way of getting a higher light output from it   
   >>>>> > without overheating. Overheating an LED kills it in short order.   
   >>>>   
   >>>>> Take for example the brake/tail lights.  These are often pulsed for   
   >>>>> tail   
   >>>>> and on for brake.  So what you said doesn't make sense.  Anything less   
   >>>>> than full voltage on (as for brake) will be lower heat.   
   >>>>   
   >>>> LEDs are current, not voltage, driven.   
   >>>   
   >>> When there's a series resistor, then you can think of them as voltage   
   >>> driven.  Anyway electronics to lower the current can be made without   
   >>> pulsing.   
   >>   
   >> No, the series resistor merely determines the maximum current that could   
   >> flow through the LED.   
   >   
   > Take for example a 6 volt DC supply connected to an LED in series with a   
   > 200 ohm resistor.   
   > 2V 20mA at the LED, 4V 20mA in the resistor.   
   >   
   > Now change the supply to 4V.   
   > 2V 10mA at the LED, 2V 10mA in the resistor.   
      
   Fuck a duck, they DID teach you something.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)