The Design of the Audio Frequency Circuit of Quenched Spark Transmitters

The paper gives the operating theory of the power transformer and alternator circuit of quenched spark gap transmitters. The secondary of the transformer and its loading capacity are reduced in the usual way to equivalent primary inductance and capacity. The theory of the transient phenomena occurring at the sudden discharge of the condenser is then developed. It is shown that under ordinary conditions the maximum condenser voltage (reduced to the primary circuit), is 1.5 times the maximum voltage generated in the alternator. The effective (or R. M. S.) condenser voltage, reduced to the primary, is found to be 0.504 times the maximum primary voltage. It is this R. M. S. voltage which is used in the usual transformer design. The theory is clearly illustrated for the case of a 500 cycle 1 K. W. set.