A Reed Switch Sensor on a surface mount PCB assembly shown in 3-D with actuating magnet. When viewed in three dimensions, the magnetic flux lines emanating from the magnet look like a beer barrel keg; and also in three dimensions, with the magnet parallel to the reed switch, the center magnetic lobe array looks like a donut and the two outside lobes look more like a boxer's punching bag -- the kind hung from the ceiling. Essentially the fields from the magnet and the fields for the lobes are symmetrical when viewed in three dimensions. As seen in two dimensions, when the magnet is brought into one of the lobes the reed switch contacts will close. Now, as seen in three dimensions the magnet can be brought into the lobes in any spherical direction for contact closure to occur. Here the magnet is moved into the sphere of influence of the lobes of the reed switch showing the closure and opening when the magnet enters the lobes and passes through them, The change in lighting signifies the closing and opening of the reed switch contacts.