Other versions exist on this site from various publications. This one is from the Radio Electronics Experimenter from 1990. The bargraph circuit uses the UAA170.
This circuit allows the division of the frequency generated by an oscillator with the 4069 by two,...
The circuit shown is a constant current source which allows the reading of resistors on a very low...
The indicator instrument of this transistor tester, from an Argentine publication of the 1970s,...