We found this circuit in the November 1975 issue of Radio Electronics magazine. It uses a digital module from the time with several adjustments. The power supply must have the indicated voltage.
Found in Popular Electronics from the 90s, this circuit uses a 2N2646 and a general-purpose transistor...
The crystal frequency of this circuit found in an American documentation is limited only by the...
These two circuits were found in Radio Electronics magazine from February 1960. The transistor is a power...