We found this circuit in an old American documentation, but the circuit can still be assembled with ease as the used components are still available. MOSFETs admit equivalents.
This circuit was obtained in a Motorola manual, but it applies to almost any operational...
Found in a 1970 EEE this circuit emulates a zener diode whose voltage can be set to R2. Power...
This circuit different from the timer was found in an English publication from 1978. The circuit uses...