Nikola Tesla Books
44 HIGH FREQUENCY APPARATUS takes the form of a large copper disc having radial slots milled across its surface and thus leaving wedge-shaped members of copper protruding for the sparking surface. The stationary electrodes were two in number, each forming a semi-circular piece of copper with radial slots and projections to correspond with the rotary member. The latter was placed upon a shaft and mounted in suitable bearings so that it could be held with its face but a few thousandths of an inch from the stationary members, and rotated at a high rate of speed. Here we have the true quenched gap, subdivided into a series of discharge points which, when the disc was rotated, split the condenser discharges into groups which were clearly defined and which imparted the beautiful musical tone to the spark. Such a gap is within the reach of the advanced amateur mechanic who is well-supplied with tools and who knows how to use them. As the gap presents no particular advantages for the apparatus described in this work, the constructional data have not been appended. Complete blueprints for a gap of 1 K. W. capacity can be supplied by the author, however, to those who are sufficiently interested to desire to build such a gap for radio work.* * For prices and specifications, see advertising pages in back of book.
