This circuit is from an old American documentation from the 70s. Transistor 2N3904 can be replaced by BC548. The relay must have 100 mA of maximum current.
In the figure we have the way to use a shift register to divide the frequency of a signal by 9....
One of the application circuits that we gave at the beginning of this sequence was a bistable...
The maximum current of this circuit can reach 500 mA with BD136 and 1 A with TIP32. The circuit...