Another disadvantage was that the o

Another disadvantage was that the output voltage was very low, due to the single currentpath through the magnetic flux. Experimenters found that using multiple turns of wire in a coil could produce higher more useful voltages. Since the output voltage is proportional to i the number of turns, generators could be easily designed to produce any desired voltage by varying the number of turns. Wire windings became a basic feature of all subsequent generator designs.However, recent advances (rare earth magnets) have made possible homo-polar motors with the magnets on the rotor, which should offer many advantages to older designs.