This is a 1946 post-war model radio. The 3-tube receiver has a long-known tube configuration.
This circuit triggers a relay when a light beam that hits the phototransistor is cut off. The...
The L7805 is the SGS equivalent of the 7805. The circuit is from the SGS linear integrated circuit...
This circuit was found in a 90s documentation from National Semiconductor. The integrated circuit is from...