To obtain a pure DC voltage, then we must consider the regulation voltages and currents that we change from AC to DC current. For that we need some settings that can support our own making and its components were easy to get in the electronics market.
This is series Power Supply that can be used on trafo 5 Ampere up to 10 Amperes.
If you want to use a larger transformer than 5 Amperes transistor 2N3055 is suggested that the double for the exit of the collector current is larger and in accordance with the current out of the transformer. How pemasanganya enough in the series on all sides of the pin.