Summary

Two high frequency air core choke coils: used in a spark transmitter to isolate the high voltage (several thousand volts) AC supply from the radio frequency voltages generated in the primary tuned circuit. Each lead from the secondary winding of the high voltage transformer is connected through one of these chokes to the main capacitor of the spark transmitter

The frequency of the current in the secondary winding of the transformer is the same as the frequency of the current from the rotary converter, while the frequency of the oscillations in the oscillatory circuit may reach millions per second. The impedance of these chokes will therefore be greater for H.F. currents than for those induced in the transformer secondary and their purpose in the installation is to prevent any rush of H.F current from the oscillatory circuit back into the transformer secondary.

Items are part of a set:
ST 021405 Rotary Converter - G. Weymouth Pty Ltd, Melbourne, Victoria
ST 021406 Low Frequency Inductance Coils
ST 021407 Transformer - G. Weymouth Pty Ltd, Melbourne, Victoria
ST 021408 Oil
ST 021409 High Frequency Air Core Choke Coils
ST 21409.1
ST 21409.2
ST 021410 Capacitor, Fixed
ST 021411 Oil
ST 021412 Oscillatory Transformer (Jigger)
ST 021413 High Frequency Inductance Coil
ST 021414 Rotary Discharger - AWA, Radio Transmitter
ST 021415 Aerial Tuning Inductance
ST 021416 Tune Indicator
ST 021417 Earth Arrester
ST 021418 Starter
ST 021419 Field Regulator
ST 21420 Morse Key
ST 021421 Tesla Coil
ST 021422 Variable Resistance
ST 021423 Coil Capacitor

Physical Description

Each of these consists of a coil of fine insulated wire wound round a hexagonal former consisting of six rectangular wooden rods, mounted between two square end plates; with two terminals on the top plate. The whole assembly is mounted on four insulating pillars on a wooden base plate.

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