A 12V power supply is a very essential and useful supply for Lab because it is used by a huge list of electronic circuits and devices. So you can build a 12V power supply circuit according to your ampere requirements.
voltage regulator IC available in 3 terminals. This IC also contains many built in features like current limit constant with temperature, thermal regulation, short circuit protection etc. The voltage of the LM338 is adjustable between 1.2 to 37 volt. But you can also use it on your desired fixed voltage between 1.2 to 37 volt. The circuit mentioned here is built to take 12V & 5 ampere fixed output from this IC. The IC will become hot during the operation due to which a suitable heatsink will be required.