| 摘要 |
PURPOSE:To extremely lower a thermal loss during irradiation of X-ray and extend the life span of switching element by selectively driving switching elements having different capacities through the change-over. CONSTITUTION:An alternative voltage supplied from a power supply 1 is rectified by a rectifying means 2 and is then smoothed by the smoothing means 3 and 4. Here, when a switching element changeover means 24 is switched to the side of contact b, this apparatus irradiates the X-ray, timing signals outputted in the specified period from a control means 19 are alternately inputted to the thyristors 20 and 22 of small capacity and thereby the thyristors 20 and 22 are alternately switched. Since a switching speed of small capacity thyristors is high, thermal loss is remarkably less even when the high speed switching is carried out as in the case of this apparatus. Therefore, switching is carried out with the small capacity thyristors 20, 22 having a high switching speed during irradiation of X-ray wherein the switching for a long period is required or with the large capacity thyristors 12, 14 during irradiation of X-ray wherein a heavy current must be allowed. |
