. The principles and practice of roentgenological technique . idge tube requii-es the useof the equivalent gap and the problem is to obtain 55 milliamperes ata 33/2 inch gap, for example, the procedure isas follows: COOLIDGE TUBE TESTING 127 Method. I The secondary terminals of the transformerare separated for a distance of three and one-half inches. The two wires, one for the lowtension current and one for the high, leadingto the negative end of the tube, are firmly con-nected. The positive wire is hooked to thepositive end of the Coolidge tube. 1. The filament is heated. The
. The principles and practice of roentgenological technique . idge tube requii-es the useof the equivalent gap and the problem is to obtain 55 milliamperes ata 33/2 inch gap, for example, the procedure isas follows: COOLIDGE TUBE TESTING 127 Method. I The secondary terminals of the transformerare separated for a distance of three and one-half inches. The two wires, one for the lowtension current and one for the high, leadingto the negative end of the tube, are firmly con-nected. The positive wire is hooked to thepositive end of the Coolidge tube. 1. The filament is heated. The degree ofheating is controlled by a rheostat and theamount determined by an ammeter. Practi-cally, it has been found that the limitationsfor radiographic and fluoroscopic work liebetween four and six amperes. Let us saythat the filament is heated to a point wherethe ammeter indicates amperes. The tubeis now ready to be energized. Without heat-ing of the filament this is not possible andthe attempt at energization would lead to de-struction of the Fig. 170 2. Where a sufficient number of variableinductances are provided, the rheostat is notto be utilized for Coolidge tube work. Thefull output of the secondary with a certaininductance is used. As a measure of safetyin accidental grounding, a fixed resistance insuch a circuit has been suggested. However,a certain inductance is selected, for examplenumber 4, the primary switch closed and thetube energized. If the discharge leaps acrossthe gap, the heating of the filament is in- creased until there is a glow between the sec-ondary terminals with an occasional blue sparkleaping between them. The ammeter readingis now made. It may be Then, withthe fourth inductance at a meter reading of
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectradiogr, bookyear1920
