. The medical and surgical uses of electricity : including the X-ray, Finsen light, vibratory therapeutics, and high-frequency currents . of the primaryor inducing current. When the secondary coil is closed, the extra currentdoes not appear in the primary coil, but by what is called reaction it isformed in the secondary coil itself, and becomes an ordinary induced cur-rent. It is called the extra current only so long as it remains in the primarycoil; it so remains only when the secondary coil is open. Cuj-rent Interrupter.—Among the different contrivances for producingthese changes in the prim
. The medical and surgical uses of electricity : including the X-ray, Finsen light, vibratory therapeutics, and high-frequency currents . of the primaryor inducing current. When the secondary coil is closed, the extra currentdoes not appear in the primary coil, but by what is called reaction it isformed in the secondary coil itself, and becomes an ordinary induced cur-rent. It is called the extra current only so long as it remains in the primarycoil; it so remains only when the secondary coil is open. Cuj-rent Interrupter.—Among the different contrivances for producingthese changes in the primary current that are necessary for induction, themost convenient is the current interrupter. In the ordinary apparatus for therapeutic purposes the vibrations rangefrom about thirty to fifty per second, but to obtain certain physiologic andtherapeutic effects much more rapid are often required—even as high asfifty thousand per minute. The higher grade of apparatus now allows of alarge range of interruptions. Fig. 34 represents a current interrupter. This when placed in the cir- INDUCTION COILS AND ELECTRO-MAGNETIC MACHINES. 53. Fig. 34. cuit of the primary coil, alternately closes and opens the circuit, produc-ing induced currents in the secondary coils. E represents the terminal ofthe iron-wire core of the coil. The hammer D is attached to the spring,which is supported to a base in the primary circuit. At the centre of thespring is attached a disk of platinum, because that metal does not corrode;B is an adjustable platinum - tippedscrew, supported by arm C, attached topost F. The thumb-screw A is forbinding screw B firm when properlyadjusted. Object of the Iro7i Core in the Pri-mary Coil.—The inductive power ofthe primary current is very greatly in-creased by putting a bar of soft ironor a bundle of iron wires in the heartof the primary coil. The iron corebecomes magnetic by the action of thecurrent, and when the current opensthe rapid demagnetization induces acurrent in
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Keywords: ., bookauthorrockwell, bookcentury1900, bookdecade1900, bookyear1903
