On Sun, 26 Dec 2010 01:17:12 -0600, G Morgan wrote:
wrote:

From some recent work, a blue LED at about 5mA drops about
3V. At 20mA the drop is closer to 3.3V. Now, put thirty of these in a
string and the difference is 10V. You only have 20V across the
resistor - it's changed 50%. ...and this is quite nonlinear.

The resistor is a current regulator not a voltage regulator.

AN LED DOES NOT HAVE A VOLTAGE DROP, the voltage can only be

bull****. LEDs have a voltage drop of 1.7V. Silicon diodes by the
way have a voltage drop of 0.7V.


Put a meter across a lit LED some time if you don't believe me.