Nikola Tesla Patents
476 70 In inductive relation to the primary p is a secondary coil s, usually of much thinner wire and of many more. turns than the former, to which are connected in a series, a receiver R illustrated as an ordinary magnetic relay, a continuously adjustable non-inductive resistance r", a battery B', of a properly determined and very constant electro-motive force and, finally, a sensitive device a', of the same or similar construction as a, which is likewise rotated at a uniform speed and which, with its brushes b" b", closes the secondary circuit. The electromotive force of the battery B' is so graduated by means of the adjustable resistance r" that the dielectric layers in the sensitive device a' are strained very nearly to the point of breaking down, and give way upon. a slight increase of the electrical pressure on the terminals of the device. It will, of course, be understood that the resistance r" is used mainly because of convenience, and that it may be dispensed with, in which case the adjustment may be effected in many other ways, as by determining the proper amount or coarseness of the sensitive powder, or by varying the distance apart of the metallic plugs in the ends of the tube. The same may be said of the resistance r' which is in series with the battery B and serves to graduate the force of the latter so that the dielectric layers of the sensitive device a are subjected to a similar strain and maintained in a state of delicate poise. The various instruments being connected and adjusted in the manner described, it will now be readily seen from the foregoing, that under normal conditions, the device. a being unaffected by the disturbances, or practically -16[This page retyped from microfilm for better readability - Ed.]
