File:Qualimeter-X-rays;The Dental cosmos (1914).jpg

Identifier: dentalcosmos5619whit (find matches)
Title: The Dental cosmos
Year: 1914 (1910s)
Authors: White, J. D McQuillen, J. H. (John Hugh), 1826-1879 Ziegler, George Jacob, 1821-1895 White, James William, 1826-1891 Kirk, Edward C. (Edward Cameron), 1856-1933 Anthony, L. Pierce (Lovick Pierce), b. 1877
Subjects: Dentistry Dentistry
Publisher: Philadelphia, S. S. White Dental Manufacturing Co
Contributing Library: Yale University, Cushing/Whitney Medical Library
Digitizing Sponsor: The College of Physicians of Philadelphia and the National Endowment for the Humanities

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Radiograph of Benoist radiochromometer.Shows 5 degrees of hardness. estimation of the amount of current used. The milliamperemeter is used for thispurpose (Fig. 3, b). This, of course, isan instrument with which everyone ismore Or less familiar, and which requiresno special description. It is connectedwith, and registers, the amount of cur-rent in the secondary circuit. Tt shouldbe stated, too. that this instrument willnot register correctly when there is anyinverse current, such as is obtained whens Ruhmkorff coil is used to actuate1 thetube. Today, however, the inverse cur-rent is not a serious source of trouble, asa well-constructed valve tube (Fig.3, d) will eliminate this objectionablefeature when a coil is employed, andwith the newer types of exciting appa-ratus, such as the interrupterless trans-former, there is no inverse current toe(ipo with. \ow as to the practical use of these
Text Appearing After Image:
Ruhmkorff coil fitted with instruments of precision. A, Bauer qualimeter. b. Milliampere-meter. c, Ammeter, for registering amount of current in primary circuit. D. Valve tube. THE DENTAL COSMOS. instruments : An X-ray tube is connectedto the exciting apparatus, and the de-sired amount of current is allowed topass. Lei us say the milliamperemeterregisters LO milliamperes. As the start-ing resistance of a tube is always alittle higher than the running resist-ance/ the current is allowed to pass fora second or two. Then the reading ofthe qualimeter is taken. Let us assumethat it is at 8. The next step is to takea radiograph of the Benoist radiochro-mometer, while the milliamperemeter isat 1 and the qualimeter at 8. Let us saythat the radiochromometric reading is 7.This means that, with this particularexciting apparatus being operated with1 milliampere, and a reading of 8 onthe qualimeter, a No. 7 B ray is obtained—that is. with this combination, a max-imum hardness of Xo. 7 Benoist is

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