Many DIY projects require a small Power Supply.
The 78XX family is ideally suited for this job, and with this little PCB you can easily build small Power Supplies for virtually every application.
The circuit is very simple:
The Alternating current is applied to X1 and rectifies by B1.
It charges a large Capacitor C1 to power the regulator.
The [...]

Switch Mode Pre-Regulator Circuit
The botheration was that a voltage regulator had to bead the 18 volt capital ability accumulation voltage to 8 volts at 500ma to ability the CD player, crumbling 5 watts of ability and causing a lot of calefaction central the bunched unit. This ambit acts as an interference-free pre-regulator to abundantly abate [...]

LM317T Voltage Regulator with Pass Transistor
The LM317T output current can be increased by using an additional power transistor to share a portion of the total current. The amount of current sharing is established with a resistor placed in series with the 317 input and a resistor placed in series with the emitter of the pass [...]