With this circuit it is possible to obtain a higher voltage from a zener diode. The circuit is from a 1970’s EEE. The device used as a constant current source is uncommon today.
This source for devices for automotive use was found in a 1985 documentation. The power...
We found this circuit in an old Popular Electronics. It is possible to light a common neon lamp...
This circuit has an opposite action to the previous one, triggering when light falls on the...