| 摘要 |
PURPOSE:To permit the voltage applied to an X-ray tube and the current flow to maintain each peak value on starting by detecting the peak value of the bulb current and setting said peak value as a standard signal, and controlling the output voltage of a filament power supply circuit so that the detected value of the bulb current becomes equal to the standard signal. CONSTITUTION:In a set voltage generator 14, the conduction width of a chopper circuit 8 is controlled so that the output voltage may be so set as enabling the filament current corresponding to the bulb current and the bulb voltage which are set in an inverter circuit 11 to be supplied. When an X-ray exposure instruction 60 is given, a high voltage is applied to an X-ray tube 5, and a current begins to flow. A sample holding signal 52 is output until the bulb current wave form 61 is completely erected after turning ON a power supply. A bulb current standard signal generator 17 outputs the max. value of the bulb current signal during the period in which the sample holding signal 52 is input, as a bulb current standard signal 53 into a conduction width controller 13, and said max. value is compared with a bulb current signal 54, and then the conduction width of the chipper circuit 8 is controlled so that the difference in the above comparison disappears. |
