| 摘要 |
582,889. X-Ray tubes. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 25, 1943, No. 13881. Convention date, Aug. 26, 1942. [Class 39 (i)] In an X-ray tube of the kind having a number of lens electrodes 22, 23 between the cathode 10 and the target 18, the potentials of the electrodes relatively to the cathode are obtained from a potentiometer 31 ... 33, and means are provided for selectively connecting the cathode to one or other of the lens electrodes without altering the potential conditions inside the tube. These consist of a common earth conductor connected to the target and to each of three pivoted contacts 40, 41, 42 biassed by springs so as to contact with the end of the potentiometer and the intermediate connections of the lens electrodes. Each contact is opened by an electromagnet 47, 48, 49 in circuit with a supply 51, 52, through a multi-contact switch 58 adapted to bridge two only of the terminals 54, 55, 56, 54<1>, the last of which is connected to the first by a jumper 57.. Movement of the switch over the successive pairs of terminals opens successively the contacts 40, 41, the contacts 40, 42 and the contacts 41, 42. The potentiometer is the secondary of a transformer, the primary of which is in the form of a number of coils 30a ... e distributed along the secondary and connected in parallel to a supply source, which may have a control device in the form of an auto-transformer 60. |
