High Frequency Apparatus Page 22

7 HIGH FREQUENCY APPARATUS LEAKASE Fig. 6.Transformer with primary on one leg and secondary on other leg of core to introduce greater magnetic leakage. The first step in the development of the resonance type of transformer duces a partial magnetic shunt that serves every purpose of the external impedance coil and which has some marked advantages over the latter device. With a correctly proportioned magnetic leakage transformer, brought to resonance by a suitable condenser connected in the oscillation circuit, the arcing at the gap is reduced to a minimum and the discharge partakes of a clear ringing tone not to be heard in other types of equipment. In addition to this marked advantage, the magnetic leakage transformer can be made to attain a degree of efficiency and a power factor not possible in the ordinary combination with its impedance coil. Secondary Potentials.-The proper potential for the secondary in the case of the resonance transformer (the term that will henceforth be applied to the low-frequency alternating current transformer designed for condenser charging) will depend upon the condenser with which it is to be used and also upon the type of spark gap employed. Since the introduction of the Federal radio telegraphic laws which govern the wave length of amateur stations, the tendency has been in the direction of higher potentials