This timer has a divider programmed by BCD switches. The circuit is from a Radio Electronics magazine from February 1989.
The configuration shown in the figure is one of the most traditional when it is desired to produce...
The transistors in this circuit from a 1994 technical publication may be BC548 and the 12 V supply...
We found this circuit in a 1977 Radio Shack brochure. Transistors can be the most modern BC548 for NPN...