Does adding more turns of wire to a coil produce a higher voltage? You wind insulated wire around three identical boxes at different counts: 150, 300, and 450 turns. Then you spin magnets inside each box using an electric screwdriver. A digital voltmeter measures the voltage each coil produces. As the magnets spin, their changing magnetic field creates a current in the wire. The more turns the coil has, the higher the voltage reading on the meter.