This power supply for gas laser (HeNe) was found in a 90’s Popular Electronics. It generates from 1300 to 1500 V using common components.
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...