The idea of this circuit found in a Radio Electronics from January 1966. The idea of the circuit is to improve the reception of audio signals, mainly telegraphy, working as a filter.
This circuit was found in an American documentation from the 90s. It can be implemented with...
This 2-terminal regulator was obtained from a 1990s National Semiconductor manual. The components admit...
This circuit uses a photocell as sensor and a sensitive relay according the power supply voltage....