Electric guitar pickups are simple devices – just a magnet for each string wrapped in thousands of turns of wire about as thin ... to measure the magnetic flux and polarity of the pole pieces.

To calculate the force on a wire carrying a current at right angles to a magnetic field, use the equation: 2 A flows through a 50 cm wire. Calculate the force acting on the wire when it is placed ...

The screws serve to conduct magnetic flux between the magnets, dragging the rotating elements along for the ride. This gearbox appears to be a refinement on [Retsetman]’s earlier design ...