A two diode full wave rectifier produces a voltage when comp
     A two diode full wave rectifier produces a  voltage when compared to ground  neutral  positive negative  positive or negative  An advantage of using series aided, two transformers circuit is  have less voltage drop  need only one bridge rectifier  will have a three point secondary connection  all of the above 
  
  Solution
1) positive or negative depending on position of diodes
when positive terminal of diodes are connected to transformer produces positive and if negatives are connected negative is produced
2) needs only one bridge rectifier

