Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Parpp807-at-aol-dot-com> John, Matt, The DC resistance of my bipolar coil is 250 Ohms. The resistance mesaured by the B-K bridge at 1 kc is 270 Ohms. What resistance is this? If it's not X sub L at 1 kc, how can I calculate it? Happy day, Ralph Zekelman