This circuit was found in a 1980s Signetics documentation. The integrated circuit is from the era. The circuit enables coded matrix control via a toggle switch.
Found in American documentation from the 90s, this configuration detects the direction of rotation...
Circuits similar to this can be found in this section. This is from 1967 General Electric...
This circuit uses two transistors and can be powered by just two small batteries. The frequency is given...