XPost: uk.rec.driving   
   From: dave@davesound.co.uk   
      
   In article <3sN4ACCMs4dRFwS6@g3ohx.demon.co.uk>,   
      Ian Jackson  wrote:   
   > Nothing is really only 'current driven'. It's more correct to say that   
   > LEDs need to be driven from a power source which provides a fairly   
   > well-defined current.   
      
   Very well defined if you're driving them hard. The source voltage is   
   irrelevant. Provided it is more than the forward voltage drop of the LED   
   or LED chain.   
      
      
   > Even when you drive them with pulsed current, the   
   > amplitude of the pulses will be determined by the voltage producing the   
   > pulses. At any instant, the power dissipated in the LED is simply the   
   > product of the voltage across it (typically 2V, depending on the colour)   
   > and the current flowing through it. When pulsed, the average power is   
   > also determined by the mark-space ratio of the pulses.   
      
   As I said, it's the current flow through the LED that you design for.   
      
   --   
   *Why do overlook and oversee mean opposite things?   
      
       Dave Plowman     dave@davesound.co.uk     London SW 12   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)