A classic power supply unit which is based on the L200 linear voltage regulator IC is presented here. This circuit provides adjustable voltage output from 3 to 20V and adjustable current limiting. R2 and R3 are used to adjust the output voltage and set the maximum current limit, respectively. The L200 is capable to provide up to 2A.
The output voltage (Vout) can be calculated from Vout=2.77(1 + R2/R4). However, it is better to use a voltmeter between the output and the ground in order to be able to see voltage in real time. For more details about voltage adjustment and current limiting, please refer to L200' s datasheet.
It is very easy to build this circuit using the PCB provided here. The input (P1 header) must be connected to a transformer which must be able to provide up to 3A. Do not miss to use an appropriate heat sink for the L200.
Artwork by: A.G
Adjustable Power Supply with Current Limiting - PCB Artwork