However,when I tried to simulate it didn't work, the output is nearly 9V, as the input. In the schematic I drew, the only difference with the proposed circuit is that I used an equivalent of 2N4403 transistor and different diodes. I also tried reversing one of the winding connections but nothing changed.
Could someone explain how this circuit works and how the output is affected by the selection of the diodes? Maybe that will also help me understand what's going wrong with the simulation.