This regulator or voltage reference consists of a variable zener diode. We found it in the June 1984 issue of Radio Electronics magazine. The output current is low.
We found this circuit on the internet. The components are current, and the time depends on C1...
This circuit was found in an English publication of 1982. The operational can be replaced by an...
With this luminous remote control, which we found in a 1990 publication, using a flashlight you...