John Chung wrote: > Took me some time to understand your idea. > > http://www.tnt-audio.com/clinica/regulators_noise3_e.html > > A picture of what it is suppose to be(based on your > description.) There are a lot of pictures there. The last is the only one that is series instead of a shunt regulator. If you lose R13, R14, and R17 you have what I suggested. You said you wanted something simple and cheap, so why are you adding parts, especially when they make the circuit worse? Take a look at the schematic for my QuickProto-01 PIC prototyping board at http://www.embedinc.com/products/qprot01/qprot2.pdf. The circuit I described powers the power supply control processor on page 2. It only have 4 parts, R6, D4, C6, and Q5. ****************************************************************** Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC consultant in 2004 program year. http://www.embedinc.com/products -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist