This isn't quite the same problem but the title still fits. I'm working on a real big LED display that's on the order of 2 miles long. Think of it as the worlds longest Christmas tree light string. When my mouth opened it yap and said "oh yah I can do that" my brain wasn't paying too much attention. Now I need to find a way to power this "thing" so it works without making the smoke come out of something. Right now I'm thinking along the lines of using a Pic controlled switching power supply to generate pwm and slowly ramping things up. I'm sure I need to have several feed points but I'd like to be sure. Anyway I was wondering if anyone has run across any good information on working with something this sized. I've got a few ideas on it but I'd like to be a bit more sure before I start. Cheers Dave The only thing that helps me maintain my slender grip on reality is the friendship I share with my collection of singing potatoes -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu