This circuit with the HA2400 was found in the March 1980 Radio Electronics magazine. The circuit has digital-gain control and must be powered by a symmetrical 15 V source.
This circuit, from a 2002 documentation, checks the logic levels of the inputs, providing a...
Using a dual 555 CMOS this very useful circuit on the bench was found in the July 1998 Electronics Now...
The integrated circuit used in this regulator is quite old. Its 1970s casing is still made of...