I have to use a DAC. The coil measures about 10 ohms, near a strong magnet. I have no way to pull up the datasheet for a voice coil in a 2.5" IDE hard drive. The closest thing this can compare to is probably a speaker.A PWM signal will not work, it just makes the coil vibrate faster, slower or stick in the full-blast position. The coil responds to voltage to move the angle.