Turning in the next place to the primary key, or signalling interrupter, it is necessary to be able to control the torrent of sparks between the secondary terminals of the coil, and to cut them up into long and short periods in accordance with the letters of the Morse alphabet.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
Let us supppse, then, that the secondary terminals of the transformer are also connected to a condenser.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
If now we adjust the Leyden jar circuit to a particular rate of oscillation, we have between the terminals of the jar or condenser an alternating difference of potential or electromotive force.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming