This circuit provides a reference voltage of 2.5 V adjusted in the trimpot. The transistor can be the BC558 (in the drawing it came out as NPN). The control is done by a rectangular input signal.
We found this circuit with SCRs and unijunction in a Radio Electronics magazine from June 1969. The...
This circuit was obtained in an old documentation, receiving the medium wave range. L1 has 20 + 60...
You can program the 4018 in other ways, as shown in the figure. In this 7 divider configuration, for...