A pair of Helmholtz coils specifically designed to fit the Teltron Tube Holder (TTT-300-100), to position alongside Teltron Tubes. Each coil consists of 320 turns of lacquered copper wire, with a coil diameter of 136mm. The coils are connected to a DC power supply (1 Amp max.) via the integral 4mm sockets, to generate a highly uniform magnetic field perpendicular to the axis of the tube, allowing the deflection of electron beams to be observed.?? Number of windings: 320 per coil? Coil diameter: 136 mm approx.? Rod dimensions: 145 mm x 8 mm dia.? Max. current: 1.0 A (continuous) / 1.5 A (momentary – max. 10 min.)? Effective impedance: 6 Ohms approx.