| 摘要 |
PURPOSE:To enable accurate X-ray photographying by comparing the output from a tube voltage regulator in step with different referential levels to display the setting voltage then varying the display with correspondence to the setting level of tube current to promote re-setting and latching the correct setting level of tube voltage. CONSTITUTION:The output from a tube voltage variable regulator 7 is fed through a rectifier circuit 15 to a comparator circuit 12 where it is compared with referential voltage in step to control lighting of LED L1-L4 through a transistor circuit 21 in display circuit 20 thus to display the setting voltage. Then the tube current is set through a tube current setting circuit 22 and if the setting level is high, a transistor Tr in shortcircuit 18 is turned on to change the lighting conditions of the elements L1-L4 thus to promote resetting of tube voltage. Consequently, the tube voltage having high setting tube current and voltage drop for regulating the regulator 7 in voltage increasing direction is corrected and latched by latching circuit 13. As a result, correct tube voltage and current are set at anytime resulting in accurate X-ray photographying. |
