13V 5A adjustable regulator using LM338
This 13V/5A power supply is based on the famous LM338 IC from the ST Microelectronics. The IC has time dependent current limiting, thermal regulation and is available in 3 lead transistor package. The IC can easily supply well over 5A at an output voltage range between 1.2V and 30V.
In this circuit the output voltage is determined by the two resistors R1 and R2.The output voltage can be varied by adjusting the R2.Diodes D2 and D3 are protection diodes. Capacitors C1 and C5 are filter capacitors while C2 and C3 are decoupling capacitors.
- Transformer T1 can be a 230V primary; 15V,8A secondary step down transformer.
- If 5A bridge is not available, make one using diodes likes SR520.
- IC1 must be fitted with a heat sink.
- An optional 6A fuse can be connected in series with the positive output terminal.
- Switch S1 can be used as an ON/OFF switch.
- 8A transformer and 5A diodes make this circuit a bit costly. So assemble this circuit only if you have real need.
- Many low cost/low current adjustable regulators for beginners are there in the power supply section.