Hi, I posted this question on the ladyada forums, but I think she was a bit too busy to answer my whole question.

For a school project, I built the miniPOV3, and I need to show why the 100omh, 4.7k omh, and zener diodes were used. I think I can best sum up my question if I just copy and paste what I posted on the ladyada forums:

1. Why is 5.6V needed for the zener diodes if the batteries are only 3V in total

2. Why exactly where the 100 omh resistors needed for the LEDs? I need to show why 100 omh resistors were needed using the equation V=IR. I got the Volts, 3, but am unsure about the total resistance and total current…do the 4.7k resistors play a role in this? Does the micro controller affect this? Basically,’m asking what parts play a role in the current, and what parts play a role in the resistance, and why those parts where used.

If you are unfamiliar with this project, you can see the schematic here:

http://www.ladyada.net/images/minipov3/minipov3schem.png

..and the list of parts here:

http://www.ladyada.net/make/minipov3/parts.html

and download the PCB layout here:

http://www.ladyada.net/media/minipov3/minipov3%20PCB.zip

I know I’m asking a lot…but I really need help

Obviously, I don’t want you to do the calculations for me…but I’m not sure I understand them myself…in class we only did very simple circuits (I chose to be ambitious…and now am paying the price :D)