Purpose:Illustrate bending of an electron beam in a magnetic field.
Description:The tube contains a point electrode at the top and a ring-shaped electrode at the bottom. A cylindrical bar magnet runs up the center axis. When powered up, an electron discharge starts at the top electrode and trails down to the ring at the bottom. When an additional 5V potential is applied to the bar magnet, as shown in the photo, the discharge precesses around the magnet.