Stereo preamplifier (CB8510E)

Found in a 90s Popular Electronics, this circuit is based on a uA739, an unusual component today.

Negative high voltage source (CB8122E)
We found this circuit at Popular Electronics. The components are still current. Changes can be...
Nanosecond pulse generator (CB9076E)
This circuit was found in ancient American documentation. Diodes are general-purpose types. |...
Frequency Synthesizer 4046 (CB25257E)
We found this CMOS circuit based on the PLL4046 in the December 1989 issue of Radio Electronics magazine....