Found in a 1980s American documentation, this crystal-controlled oscillator generates 100 MHz signals. The crystal used is 20 MHz. Modern equivalent transistors can be used.
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
This circuit provides an output voltage with the absolute value of the charge and discharge current...
With the figure circuit it is possible to control the amount of heat generated by the heating...