This circuit is for 12 V batteries but can be used with batteries of other voltages by changing the zener diode. The trigger point is adjusted by R1. The operating system accepts equivalents.
This circuit, which can act as a shield, was found in a 1990 PE Hobbyst Handbook. The circuit...
This circuit regulates negative voltages based on regulator 723. The maximum output current will...
This different configuration of voltage regulator with transistors in series and in parallel was...