High Frequency Apparatus Page vii

PREFACE This volume has been prepared in response to a general demand created by a series of articles which appeared in Electrician and Mechanic, Popular Electricity and Moders. Mechanics, and The World's Advance. The articles covered briefly the apparatus employed in an experimental study of high frequency current phenomena over a period of several years. In this work, I have spared no effort to produce a treatise of practical value. Theory has been ignored chiefly because it would serve merely to confuse the non-technical reader. The designs offered are more than theoretical-they are the result of actual construction and experiment. In many cases, the entire oscillation transformer has been rebuilt and rewound many times before satisfactory results were obtained. The work has been divided into six basic parts. The first two chapters tell the uninitiated reader what the high frequency current is, what it is used for, and how it is produced. The second section comprising four chapters describes in detail the principles of the transformer, condenser, spark gap, and oscillation transformer, and covers the main points in the design and construction of these devices as applied to the work in hand. The third section covers the construction of small high frequency outfits designed for experimental work in the home laboratory or in the class room. The fourth section is devoted to electro-therapeutic and X-Ray apparatus. The fifth describes apparatus for the cultivation of plants and vii