If a conductor, usually a wire, carries a current and is placed in a magnetic field, it experiences a small force. Electric motors are a good example where such a force occurs. To measure this small force you need a very sensitive balance-like this one! This unit's design assures highly accurate measurement of these small forces. Force vs. current or force vs. conductor distance can be determined easily. A series of built-in multi-turn coils can be utilized for multiple runs of the experiments. Includes two 1-ohm, 25-W resistors for current limiting, instructions for assembly and experiments. Requires two DC power supplies capable of delivering 5 A.