The Harmonic Mode of Oscillation in Barkhausen-Kurz Tubes

The phenomenon of harmonic operation of Barkhausen-Kurz tubes employing a resonating helical grid is investigated by the use of tubes with the plate cut transversely into three sections. It is shown that the fundamental or Barkhausen frequency may be elicited by exciting the grid at its central portion, but that if the grid is excited at its ends either symmetrically or unsymmetrically the oscillations occur at double the Barkhausen frequency. This doubled frequency is that usually generated by tubes of this type. It is also shown that it is essential to tune the filament circuit of the oscillator if maximum power output is desired.