This TTL circuit uses LED indicators and must be powered by a voltage of 5 V. The capacitor determines the speed of the draw. We found it in documentation from the 90s.
The transistor can be a modern equivalent and the transformer is the type of output found on an...
The output voltage of this unit is approximately 1.4 V less than that of the chosen zener. The...
We found this circuit in an English publication from the 80's. The circuit uses current components like...