Deflection e/m Tube
For determining e/m by balanced electrostatic deflections or by magnetic deflection using the Helmholtz coils.
Simple electrostatic and magnetic deflection may be demonstrated and the relationships shown between the plate potentials or coil currents and the degree of deflection. The ‘electron mirror’ effect producing trochodial spirals is easily shown and also the magnetic focusing at points along the trochoid.
The tube is the standard glass sphere with cylindrical neck and has a diode electron gun with filament and cylindrical anode. In the centre of the sphere and angled at 15° across the axis is a mica screen 90mm long x 60mm high approximately, divided 2 to 10cm along its horizontal axis and 2-0-2cm vertically. The undivided side is coated with phosphor and produces a clear fluorescent trace when irradiated by the electron beam. The top and bottom edges of the mica plate are supported by horizontal metal plates which are connected to 4mm plugs in the side caps and provide the electrostatic deflection field when connected to an E.H.T. supply.
• Maximum filament voltage: 7.5V.
• Anode voltage: 1500 to 5000V.
• Typical operation: 2000 to 4500V.
• Anode current: 1mA.
Supplied complete with instructions.