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.
The CMOS TLC555 can be gated from external CMOS circuits using the configuration shown here. The...
In the figure we have a two-channel preamplifier with two 741 integrated circuits. The circuit is from a...
We found this circuit in a documentation from the 50's. The transistors are germanium types. The...