> That does not exactly raise my confidence in the engineering > behind the part of the circuit that is shown "a little knowledge is a dangerous thing" ? A potentially, no pun intended, harmful circuit that raises as many questions (if you know you ask them that is) as it answers. In a situation like this I would much rather over-engineer for safety's sake -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist