This traditional signal injector configuration was obtained in a 1977 amateur radio manual. The frequency is given by the capacitors and the supply can be made with 1.5 or 3 V.
This is a MOSFET version of a grid dip meter for frequencies between 1.8 MHz and 150 MHz,...
This configuration was found in a 1988 documentation. It is a touch lift drive system. The circuit...
A configuration using three of the four voltage comparators on the LM339 is shown in the figure and...