This circuit is from an American 80's documentation. The circuit indicates when the voltage of a 9 V battery drops below 7 V. The transistors can be BC548.
This application, shown in the figure, is nothing more than a practical circuit to prove a 4093...
One of the application circuits that we gave at the beginning of this sequence was a bistable...
This shield circuit for controlling the direction of rotation of DC motors with current up to 500...