This circuit of a 1969 Electronic Design uses RTL logic. The setting can be adapted to TTL. The frequency is given by the crystal.
This circuit, from a 1990 documentation, can serve as a basis for a game of target-game. The...
While BC547 is not a suitable transistor, it can work on this circuit. The ideal would be the...
This power supply that we found in an old American documentation uses an integrated circuit that...