This circuit was found in the February 1983 issue of Radio Electronics magazine. It is a 4-digit circuit with dedicated integrated circuits, with no power supply indicated.
This simple musical instrument was obtained from a 1967 magazine. If the original transistors are...
The transistor of this circuit can be the BC558. The circuit is from an old documentation...
We found this circuit in an old American documentation for hams. The circuit serves as a telegraph...