Free circuit schematics - wiparat.com

In this circuit, the 7815 regulatates the positive supply, and the 7915 regulates the negative supply. The transformer should have a primary rating of 240/220 volts for europe, or 120 volts for North America. The centre tapped secondary coil should be rated about 18 volts at 1 amp or higher, allowing for losses in the [...]

0-15v variable power supply
This is easy circuit power supply, variable regulator adjustable voltage output 0V to 15V and Current adjust 0A to 1Amax. Use normal electronics part.
TR1 provides a constant current to a bank of three zener diodes, thus maintaining a constant voltage independant of supply voltage variations. The resistor Rx is used to sense [...]