This circuit is from March 1978 Radio Electronics. The 4-digit circuit uses a period module and is battery powered. The main integrated circuits are CMOS and TLL.
The oscillator shown in the figure generates a rectangular signal with a 50% active cycle (square)...
This power supply can be implemented with a TIP32 providing an adjustable output at the 2k2...
This switched circuit was found in an old documentation and no information about the transformer...