Nikola Tesla Patents
540 Per B " 4 Rin Fig. 1 A designates a primary coil forming part of a transformer and consisting generally of a few turns of a stout cable of inappreciable resistance, the ends of which are connected to the terminals of a source of powerful electrical oscillations, diagrammatically represented by B. This source is usually a condenser charged to a high potential, and discharged, in rapid succession through the primary, as in a type of transformer invented by me, and not well known. But when it is desired to produce stationary waves of great lengths, an alternating dynamo of suitable construction may be used to energize the primary A. C is a spirally wound secondary coil within the primary, having the end nearer to the latter connected to the ground E", and the other end to an elevated terminal E. The physical constants of coil C, determining its period of vibration, are so chosen and adjusted, that the secondary system E CE is in the closest possible resonance with the oscillations impressed upon it by the primary A. It is moreover of the greatest importance, in order to still further enhance the rise of pressure and to increase the electrical movement in the secondary system, that its resistance be as small as practicable and its self-induction as large as possible under the conditions imposed. The ground conception should be made with great xits a care, with the object of reducing the resistance. Instead of being directly grounded as indicated, the coil C may be joined, in series or otherwise, to the primary A, in which case the latter will be connected to the plate E. But be it that none, or a part, or all the primary or exciting turns are included in the coil C, the total length of the -5
