Here is the circuit diagram of a powerful 12V regulator that can deliver up to 15 A of current.The common voltage regulator IC 7812(IC1) is used to keep the voltage at steady 12V and three TIP 2599 power transistors in parallel are wired in series pass mode to boost the output current. The 7812 can provide only up to 1A and rest of the current is supplied by the series pass transistors. The 15A bridge B1 does the job of rectifying the stepped down AC input. The capacitor C1, C2 and C3 act as filters. The 1A fuse F1 protects the IC1 from over current in case if the pass transistors fail. The 15A fuse F2 protects the entire circuit (especially the pass transistors) from over current.
With high current transformer, power transistors and high current bridge the circuit is a bit costly and you may try this only if there is a serious need.
- Assemble the circuit on a good quality PCB.
- The T1 can be a 230V AC primary, 18V secondary, 15A type transformer.
- The B1 can be a 15A bridge.
- If 15A Bridge is not available, make one using four RURG1520CC diodes.
- The IC1 and transistors must be mounted on heat sinks.