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.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...