This reinforcing stages from a 1960s documentation. No information is given about the transformer and the transistor admits equivalents.
Found in Electronics Today International in the 90s, this circuit turns an operational on and off...
At dusk this circuit triggers a relay switching lamps. The circuit can be powered from 6 to 12 V...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...