Nikola Tesla Books
THE ALTERNATING CURRENT 5 so design his apparatus that it will operate in a satisfactory manner on the circuit at hand. In the various descriptions of transformers which follow in later chapters, the data for all standard frequencies are given in order that the worker need not make computations unless he so desires. In addition to this, one entire chapter is devoted to a simple explanation of the principles of transformer design, and, from this explanation, the average worker will be enabled to work out any special design that may appear desirable. The High Frequency Current.-When an alternating current is made to change its direction of flow many thousands of times per second, it is termed a "high frequency current." The precise figure at which this term is properly applied is not very clearly defined but it is usually placed at the mark of 10,000 cycles per second. From this, it may extend into the hundreds of thousands or perhaps millions of cycles per second. How this current, which oscillates with such inconceivable rapidity, is produced will be duly explained in the next chapter, but first of all let us consider the peculiar characteristics of which it partakes and the uses to which it may be put. Characteristics of the H. F. Current.-For the serious experimenter and student of modern electricity, there is no more fascinating study than that of the electric current at high potential and high frequency. The phenomena which may be exhibited through its agency are at once spectacular and startling, of inconceivable beauty and grandeur, and, in practical applications, of the greatest utility and importance. While the larger types of apparatus demand that the utmost care and the finest materials be used in the construction, the youthful experimenter may satisfy his craving for immediate results by building temporary apparatus of the crudest construction imaginable
