With the capacitor used, this circuit provides delays of 40 to 60 seconds. Larger capacitors can be used, and the SCR supports an equivalent. The circuit is from the 1977 RC semiconductor manual.
This tachometer from a 1994 publication has a bargraph scale with the well-known LM3914 integrated...
This traditional sensor configuration with LDR was found in a 2001 documentation. The integrated circuit...
The L7805 is the SGS equivalent of the 7805. The circuit is from the SGS linear integrated circuit...