The PSU-12 was designed as a reduced version of the PSU-8, where only two rails and a reduced size were required. It features two adjustable rails using the LM317 and LM337 devices.

The PSU-12 uses the same circuitry as the PSU-8, but is more compact. It is primarily used for audio power supplies, and a 15-0-15 (30VCT) transformer is adequate to generate a regulated +/-16V rail.

PSU-12 Circuit (pdf) PSU-12 BOM (pdf) LM317 Data sheet (pdf)
PSU-12 PCB (pdf)   LM337 Data sheet (pdf)


The LM317/337 devices will require heatsinking of some form for most applications. The size and type of heatsink will depend on teh application and the mechanical design of the equipment. In many applications I use a 3mm bracket to the sub-assembly baseplate, which is adequate. Thermal past is required to get good thermal conduction between joining surfaces, and the regulator tabs need to be electrically insulated from the heatsink.
















PSU-12 Module


PSU12 assembly











PSU-12 module with transformer as a subassembly.