This simple clock can be used to generate signals up to 100 kHz, depending on the crystal. We found it in a 1967 documentation. Note the high supply voltage.
This simple game in which the player has to guess the chosen position of the key was found in a...
This circuit was obtained from an English documentation from 1995. The operational amplifier has...
This circuit provides just over ½ W to a small speaker. We found this configuration in an old...