Free circuit schematics - wiparat.com

A high qualitiy voltage regulation must be built using high quality parts. It is however no longer necessary to use discret semiconductors as there are now very good integrated voltage regulator ciurcuits available. I chose the adjustable regulators LT1085 (positive) and LT1033 (negative) which are compatible to LM317/LM337. The standard fixed voltage regulators of the [...]

This circuit above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0.7 Volts are dropped across the transistors b-e junction, leaving a higher current 12.3 Volt output supply. This circuit can supply loads of up to 500 mA. This circuit is also known as an amplified zener circuit. Link
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