Adjustable reference (CB21540E)

We found this circuit with 5.3V zener in a Philips publication from the 60s. The op amp could be a modern equivalent.

Divider by N with the 4017 (2) (CB12131E)
With this circuit it is possible to divide the frequency of a rectangular signal by values between 2...
Precision Hysteresis Alarm (CB26242E)
This circuit was obtained from the Encyclopedia of Electronic Circuits volume 5 of 1995. The...
High Voltage Regulator (CB19513E)
This circuit can supply output voltages from 50 to 250 V from an input voltage of 300 V. The...