This circuit was obtained in a 1967 Electronics World. The components are still common today, the SCRs can be replaced by equivalents and the unijunction transistors the 2N2646.
In the figure we have the way to use a single control voltage to act on two varicaps...
This oscillator provides a 1 MHz rectangular signal determined by the capacitors used. The circuit...
This shield circuit with an optical coupler was found in an 90s EDN. The circuit can be used with...