Inactive voltage doubler circuit

The circuit in the first current diagram is not functioning.

Which connection among the following should be removed: 1 to 2, 2 to 3, 3 to 4, 3 to 6, 4 to 5, 5 to 6, or 6 to 1, to make the circuit operate as a voltage doubler and half-wave rectifier?



The answer is the segment 1 to 6 (second picture,) but I’m not sure why that connection needs to be removed.

The voltage doubler circuit I referred to only uses a two-terminal transformer with a similar component configuration, and it works.

I can’t yet understand why a three-terminal transformer would behave differently.



The problem in the first diagram is that half of the transformer is shorted out:



By connecting point 2 to ground and point 6 to ground, you have shorted out the half of the transformer between points 2 and 3.

Admittedly, the direct answer to the question is to remove the short-circuit. As to what should be the correct circuit, it depends on the needed output voltage. Since "voltage doubler" is mentioned in the title, this is not what is achieved by using the central tap:



C1 is charged with the full secondary peak while C2 is added only half the secondary voltage. To reach the full doubling, \$V_{o2}\$ should not be connected to the central tap, but to \$V_{-}\$. This will double the secondary voltage:



The voltage doubler circuit I referred to only uses a two-terminal transformer with a similar component configuration, and it works.

Just ignore the central tap to achieve the same.

I can’t yet understand why a three-terminal transformer would behave differently.

Each half works as a voltage source in phase with half the amplitude. That's the reason you only get 1.5 times the secondary voltage just by removing the short circuit.

Connection 1 to 6 is not the one that needs to be removed, the connection to remove is point 2 to the center tap of the transformer. This should make it a standard voltage doubler circuit.

Also you probably don’t want to connect the primary side center tap, you should only have two connections to the mains voltage.

And you show some numbers labeling parts of the circuit that are the same numbers except some are circled. Those should not be connected (example 2 and circled 2). I would remove all of those labels and only use non-ambiguous labels. Take your original circuit, remove the center tap connections and labels and redraw it, preferably using the built editor here or a screenshot of the circuit inva proper schematic editor. If you must hand draw it at least make it neat. Post that and we’ll see if it’s correct.