This is a circuit diagram for a powerful 12V regulator that can handle up to 15 A of current. The rummage-sale voltage regulator IC 7812 (IC1) keeps the voltage at a constant 12V, and three TIP2599 power transistors in parallel are underwired in series to enhance the output current.
The 7812 can only give up to 1A, and the series permit transistors to provide current respite. The process of correcting the stepped downcast AC input is done by the 15A bridge B1.

TIP2955 as Voltage Regulator Circuit
The capacitors C1, C2, and C3 in this circuit act as filters. If the pass transistors flop, the 1A fuse F1 protects the IC1 from an excess of current. The 15A fuse F2 protects the entire circuit from overcurrent (especially the pass transistors).
When working on circuits that use current transformers and high current consuming bridge circuits, this circuitry is expensive, and you should only use it if it is absolutely necessary.