With this circuit, from an Argentine publication from 1973, 12 V continuous output can be obtained with a 6 V transformer. The diodes can be 1N4002 or 1N4004 and potentiometer R2 must be 4k7 of wire. The secondary current of the transformer is 500 mA at 2 A. R1 can be 220 ohms x 1 W.
