Using the 741 this basic circuit was found in the November 1973 Radio Electronics magazine. The power supply must be symmetrical. The components can be recalculated for other frequencies.
This capacimeter was obtained in European documentation from the 1980s. The indicator instrument, a...
This circuit for the logic control of the 555 in a power supply was found in the October 1989...
This configuration with the LM111 was found in your factory manual. The circuit can be implemented with...