Dumitru Stama wrote: > I think i overlooked this part but not by mistake but because i > thought 2v headroom means 2v between + and -. Headroom refers to the extra supply voltage needed beyond the useable input and output voltage ranges. If I remember right (your job to look up) a TL072 needs about 2V more supply on each end than the min/max signal voltages it is handling. In other words, if you want to handle 0-5V signals, the supply needs to be -2V to +7V. ****************************************************************** 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