Oscillators
with Crystals Having Two Sets
of Electrodes
The original crystal oscillator devised by Dr. Nicolson, as well as a
number of the earlier crystal oscillators tested by Dr. Cady, employed crystals
with, effectively, two pairs of electrodes. The basic circuit is shown in
figure 1-156. The re quired phase inversion of, the amplifier output voltage is
provided by the crystal unit operating at a mode for which the polarities of
the plate and grid terminals with respect to ground are 180 degrees out of
phase. The circuit shown operates the crystal unit very
