Report Transformer and LM317 Question in Electronic Projects Design/Ideas Posted January 25, 2006 Ahhhhh yes....... I should have checked the data sheet first. Yup, since the reference voltage is between the output pin and adjust pin (not adj pin to common... I guess I've been around TL431's too long), any resistance in series will screw up the load regulation (not line regulation). As for the capacitor C1..... I have had circuits with a LM338 oscillate under certain line/load conditions without out it ("conditionally stable").thanks for the reply.Actually, i still not fully understand the statement "any series resistance will screw up the load regulation"Can explain further?