This circuit was obtained from an American technical manual from the 80's. The integrated circuit is an operational of the time that can be replaced by a modern equivalent.
This circuit that uses only transistors indicates when the voltage in the circuit has the voltage...
This is the circuit of a robot published in the June 1992 issue of Radio Electronics magazine. The sensors...
This circuit was found in a 1980s documentation. It decodes by identifying a certain frequency tone...