Found in a Popular Electronics this circuit has double regulation. The integrated circuits used provide a maximum current of 1 A and must be provided with heat sinks.
Found in a 1965 Radio Shack documentation this oscillator can be used with modern general purpose...
In the figure we have the way to use a single control voltage to act on two varicaps...
Found in a 90s documentation, this switch that is also sensitive enough to operate capacitively uses...