This circuit was found in the December 1992 issue of Radio Electronics magazine. The current is a few mA and the maximum input voltage is around 12 V.
The circuit shown in the figure is suggested by Maxim (www.maxim-ic.com) and makes use of the...
We found this circuit in a Radio Electronics magazine from January 1975. The transistors are...
Found in documentation from the 1980s, this circuit can have several adaptations to use modern...