Something that I've been wondering about, as I look at high voltage sparks. Within a single spark, along its length, there are sometimes zones that are much brighter than the rest of the spark. A given spark might have three or four of these, or none. Any ideas what causes this? Could it be my eye rather than the spark? --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .