Found in the July 1970 Radio Electronics magazine, this circuit has an adjustable activation time that depends on capacitor C1. The SCR may be a 106 series equivalent.
Found in a 1960 Sylvania manual, this circuit can be implemented with a modern equivalent...
This configuration, already presented in other points of this section and website, is of a...
We found this precise crystal oscillator for the 144 MHz band, depending on the crystal used. The...