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 control from a 1989 publication can be assembled with several equivalent components. The SCR,...
In the figure we have a circuit suggested by National Semiconductor, using an operational...
This circuit was obtained from an English magazine from 1976. What this circuit does is start from...