Justin Richards wrote: > I guess at resonance the load appears completely resistive and current > is in phase with voltage. Resonance center and pure resistive impedence are not always the same thing= , although usually close. The resonance peak is usually the easiest thing to measure. For quick and dirty tuning it's probably enough. ******************************************************************** Embed Inc, Littleton Massachusetts, http://www.embedinc.com/products (978) 742-9014. Gold level PIC consultants since 2000. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .