Highly evacuated electron tube with focusing electron gun and inclined fluorescent screen so the path of the beam can be seen and the effects of electric and magnetic fields can be studied. The electron beam can be deflected electrically in the electric field and magnetically by using the Helmholtz coil pair (B8A49475). By adjusting the electric field so that it cancels the magnetic deflection, it is possible to determine the specific charge e/m and the velocity of the electrons.

Simple electrostatic and magnetic deflection may be demonstrated and the relationships shown between the plate potentials or coil currents and degree of deflection. The 'electron mirror' effect producing trochoidal spirals is easily shown and also the magnetic focusing at points along the trochoid.

The Deflection e/m 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 measuring approximately 90mm in length and 60mm in height. 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 an E.H.T. Power Supply.

Technical Specifications:

• Maximum filament voltage: ≤7.5V AC/DC
• Maximum anode voltage: 5000 V
• Anode current: approx. 0.1 mA at 4000 V
• Maximum capacitor voltage: 5000 V

Dimensions:

• Glass bulb: approx. 130 mm diameter
• Total length: approx. 260 mm
• Fluorescent Screen: approx. 90mm x 60mm

Requires the following equipment to operate:

• B8A49463 - Universal Stand
• B8R02653 - EHT Power Supply - to power the anode & deflector plate
• B8R07149 - EHT Experiment Leads (4 required)
• B8G85458 - Bench Power Supply - to power the filament
• B8R06545 - 4mm Leads
• B8A49475 - Helmholtz Coils
• B8G85483 - College Power Supply Unit - to power the Helmholtz Coils