Found in the September 1972 issue of Radio Electronics magazine, this signal injector is based on the HEP580. The circuit is powered by two batteries and its frequency is basically given by C1.
The UAA180 integrated circuit is no longer manufactured, but if the reader finds one in a scrap...
Found in a 1967 General Electric SCR manual, this circuit uses a neon lamp to produce opposing SCR...
This circuit was obtained in the manual of the used integrated circuit. Equivalents may be used...