The center tap of the secondary is grounded. The top of the winding goes to the anode of D1 and the bottom of the winding goes to the anode of D2. The cathodes of the diodes are tied together and go to the positive side of a capacitor. The negative end of the cap is grounded. There is a resistor in parallel with the cap. The wave form shows a full wave rectified sine wave in thin lines like that in figure 3.8. A heavy line follows the sine wave up to its peak. At the peak the thin line sine wave falls away and the heavy line falls slowly on what looks to be a straight line. When the slowly falling heavy line and the rapidly rising thin line intersect the heavy line is pulled upward to the peak and the cycle repeats. End verbal description.