GB616491A - Improvements in or relating to x-ray apparatus - Google Patents

Abstract

616,491. Supply systems for space discharge apparatus. PHILIPS LAMPS, Ltd. Sept. 6, 1946, No. 26868. Convention date, March 3, 1943. [Class 38 (iv)] Condenser arrangements.-In order that the voltage of a condenser supplying an X-ray tube, and being charged by rectified current, may reach a value equal to or greater than the maximum value of the alternating voltage, notwithstanding the resistance of the charging circuit, an inductance is included in the said circuit which is so rotated to the resistance and capacity thereof that its stored energy continues to raise the condenser voltage when the voltage of the charging current is less than that of the condenser. The magnetic flux in the inductance, which may be the leakage inductance of a supply transformer, is preferably so chosen that the condenser voltage is substantially constant. The load circuit may be periodically interrupted to remove its influence on the charging, as when the tube voltage is inadequate to generate rays of the desired hardness. Fig. 4 shows an X-ray tube circuit in which the condenser 1 is charged through a rectifier 5 and resistance 2 from a transformer 4, the inductance of which, if not sufficient, is supplemented by an inductance 6. In order to cut off the tube 3 when the voltage is insufficient, a grid 7 is biassed to a voltage dependent on the charging current by a connection to a tapping on the resistance including a voltage 9 so that the tube may conduct only when the charging current is substantially zero. Alternatively, a polarized relay may control the load circuit.