This oscillator for the fifth overtone of a crystal was found in a Radio Electronics magazine from May 1970. Transistors are RF types, and the transistor determines the maximum frequency achieved.
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...
In the figure we have three voltage doubler configurations that can be used in high and low...
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...