One practical and cheaper approach to reduce ripple voltage is to use an off the shelf 3 –terminal IC voltage regulator, such as a LM78xx ( where “xx” stand for the output voltage rating ) for a positive output voltage or its inverse equivalent the LM79xx for a negative output voltage which can reduce the ripple by more than 70dB (see datasheet) while delivering a constant output current of over 1 A. Figure 4 depicts picture, pin diagram, and a typical circuit of a 12V 3-terminal IC voltage regulator in TO220 case style