Abstract

It is assumed that the average reader of this treatise will be familiar with the elementary principles of wireless apparatus.  Granting this, it is, of course, reasonable to believe that such readers will understand how an oscillatory current is set up in a circuit comprising an inductance or coil of wire, a capacity or condenser, and a spark gap. The condenser is charged with a high tension current from any convenient source such as a transformer or induction coil, and when the potential stored up in the condenser reaches a critical value, the air in the gap between the spark gap electrodes can no longer stand the strain, and the condenser crosses the gap in one direction, it literally over-reaches itself just as a pendulum swings past the neutral post when given a push with the hand. When the first rush of current passes in one direction, a reserval of the cycle occurs and a second rush in the opposite direction is effected. This operation is repeated many thousands of times per second, the discharge gradually dies down until all the energy is either completely radiated or used up in heat or performing work. The oscillations cease once the potential across the condenser has been lowered to such an extend that the spark can no longer jump the air gap. The Condenser immediately takes a fresh charge from the transformer and the entire cycle of operations is repeated. It will be understood that all of this passes in an infinitesimal fraction of a second, the charge and discharge of the condenser taking place so rapidly that the observer can detect no change in the solid spark which appears continuously to fill the gap.