This circuit is from the 1983 Intersil Databook. The display is plasma and must be excited by a high voltage circuit. The components used in this configuration are not common today.
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...