15.4. SERIES AND PARALLEL INDUCTORS497A pair of inductors can be seen on this circuit board, to the right and center, appearingas small black chips with the number ”100” printed on both. The upper inductor’s label canbe seen printed on the green circuit board as L5. Of course these inductors are very small ininductance value, but it demonstrates just how tiny they can be manufactured to meet certaincircuit design needs.15.4Series and parallel inductorsWhen inductors are connected in series, the total inductance is the sum of the individual induc-tors’ inductances. To understand why this is so, consider the following: the deﬁnitive measureof inductance is the amount of voltage dropped across an inductor for a given rate of currentchange through it. If inductors are connected together in series (thus sharing the same current,and seeing the same rate of change in current), then the total voltage dropped as the result ofa change in current will be additive with each inductor, creating a greater total voltage thaneither of the individual inductors alone. Greater voltage for the same rate of change in currentmeans greater inductance.