| 摘要 |
PURPOSE:To spread the range in the vicinity of the peak value by reducing the voltage applied to a high-voltage transformer by superposing the AC voltage in the reverse polarity during the period in a specific phase of the AC voltage, in order to increase the amount of the generated X-ray by forming the wave form of the voltage applied to an Y-ray tube nearly to a trapezoid form, in the case of an X-ray apparatus having an improved high-voltage generating circuit. CONSTITUTION:When an X-ray exposure instruction is transmitted, e1 is applied during the period from zero degree to theta1. When a phase theta1 is reached, a switch 15 is turned OFF, and a thyristor 16 is turned ON. The differential voltage (e1-e2) between the output voltage e1 of a transformer 2 and the output voltage e2 of a transformer 18 is applied to the primary coil of a high-voltage transformer 5 through the thyristor 16. When a phase theta2 is reached, the voltage e1 is applied again. (e1-e2) is applied at a phase of (180 degree + theta1), and e1 is applied again at a phase of (180 degrees + theta2). In an X-ray tube 7, the voltage variation on turning ON/OFF of the switch 15 is reduced by the filter effect due to the leak inductance of the high-voltage transformer and the floating capacity of high-voltage cables, and the wave form of voltage in a wide range in the vicinity of the peak value can be applied. |
