This simple TTL siren was found in a 1980s Electronics Today International. The power supply is 5 V and the integrated circuit can be the 7400.
This source, found in a publication from the 1980s, uses an integrated circuit that is uncommon today....
The circuits shown in the figure, that of an infrared video signal transmitter and receiver, were...
This high current regulator for TTL circuits was found in an old French documentation from the...