Focussing coil for beam tube electromagnets - is in two parts which are fed from common supply and one part has high impedance and other part has low impedance

摘要

Focussing coil for electric - magnets and associated with electron beam tubes. The design is intended to overcome the problem of modulation, high field intensity and the need for a common electrical power supply. The electro -magnets are basically fed from two separate coil windings. The first, of low impedance, provides 80% or 90% of the required field. The remaining coil has a high impedance and superimposes a variable field to make up that required. The two coils are in parallel and present a nominally constant impedance to the supply. The physical arrangement is such that main and auxiliary coils are alternated along the length of the focussing region, the main coils starting and finishing the sequence.