Found in a 300 Circuits from the 90s, this circuit can deliver a maximum current of 50 mA. The output is 20 V with a 12 V input.
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...