Klaas Robers wrote:I see, you have 8 strings of 5 diodes.... That is 8 x 25 mA = 200 mA for peak white. Don't allow to run more for a somewhat longer time as that will ruin your LEDs.
I see that you are not familiar with the way a transistor or a darlington pair works. I see you calculating the worng things.
OK, I have read this detailed explanation a number of times, and will continue to study it carefully. What happens is that I try to find a logically consistent explanation for things given my basic lack of experience and training. And then I document it on the forum here so that people can correct me. As I see, and you have explained, I did not understand things well at all. Your explanation is fantastic - a big thank you. What I think I was concerned about before was the current somehow making it "backwards" through the transistor and frying the Arduino. But I understand now that if the LED array is limited by the resistor, and the TIP has a 250x Ib:Ic ratio then the current on the Arduino pin is also limited and no resistor required. Thanks again.
I appreciate your assistance Klaas; invaluable! I wish I had so much knowledge. At least this time around I'm taking the time to build up a better understanding