Wow, that'll do for further investigation for the flow meter. Thanks Colin :: LT1013/4 - Dual/Quad precision op-amp with a number of circuits on :: the :: :: datasheet for using a single quad op-amp with one section :: as the :: cold junction compensation reference, and the other three :: sections :: to sense 3 thermocouples before using a mux. Also has :: circuits for :: hot wire anemometer and liquid flow sense (I should have :: remembered :: these for the recent discussion where someone wanted airflow :: measurement)and strain gauge signal conditioner. -- cdb, colin@btech-online.co.uk on 23/11/2006 Web presence: www.btech-online.co.uk Hosted by: www.1and1.co.uk/?k_id=7988359 Do No Harm. We must never do evil that good may come of it: William Penn 1693 . -- No virus found in this outgoing message. Checked by AVG. Version: 7.5.431 / Virus Database: 268.14.13/546 - Release Date: 11/22/2006 9:01 AM -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist