Let's learn about the transistor series voltage regulator with short circuit and overload protection. And how it reduces ripple.
Learn Unregulated power supply! Here an important basic. You should know. Diodes rectifier, Designing, reduce ripple, capacitors filter.
This is dual 15v power supply schematic, using LM7815,LM7915,and power transistor and zener diode for voltage stable voltage 15 volts positive and negative. [...]
Small Zener diode voltage regulator circuit with PCB, using transistor and few parts. it is simple and cheap fixed dc source circuit. As one of best choice.