
21 6
Analog Electronics
at switch-on, a most undesirable characteristic.
That of Figure
8.2()d
is representative of the
current switching and Vakar oscillators and is very
suitable for a high-stability oscillator. That of
Figure
8.20e
results in an amplitude of oscillation
which is very prone to amplitude variations due to
outside influences. It is therefore excellent for a
simple radio receiver designed to achieve most of
its sensitivity by means of reaction, also known as
regeneration, such as that shown in Figure
8.21.^
With this circuit, as the reaction is turned up, the
effective circuit Q rises towards infinity, providing
a surprisin