Lower voltage diode the other side of a step up transformer?

No. At least if you are really meaning what you said here. I'm assuming this is some kind of mains to low voltage psu. Surely, putting the rectifier diodes is going to be on the secondary in any case. Depending on what you want, it can be done several ways. If the transformer has two ends to the secondary, ie no centre tap, then you need a bridge rectifier to allow both halves of the ac waveform to be rectified. If it has a centre tap then you have one rectifier from the ends, ie one for each and the centre tap as 0V Or you could use two bridges, isolating the centre tap and get two supplies. Lastly, the least efficient way is one half wave rectifier across the secondary, but then you are only really using one of the cycles of the mains in effect. Brian

No.

What IQ did you say you had? I think whoever told you was lying.

You need to expand on what you're trying to achieve.

Ah. Humor. Thanks for the laugh.

no, he definitely needs to shrink his posts. It's all trolling

LOL!

Ocassionally he does ask a real question because he needs the answer to it.

It was funny in more than one sense.

As long as one is adding diodes, may as well build a doubler on the output side. Two topologies suggest themselves.

A center-tapped secondary could be useful too. All sorts of possibilities.

I think I just invented the non-integer-ratio voltage multiplier.

Their outputs tend to be noninteger ratio voltages in practice, the more stages the more the voltage drops from no-load value.

No, the transformer will turn it back into AC. It responds to /changes/ of current and a half wave will go up and then down resulting in +ve and

-ve from the secondary.

Yer-but, the issue is over the transformer being subject to a DC voltage which in the case of the OP will be: 230V x sqrt(2) x pi / 2 being developed across the transformer. That will produce a net DC current in the transformer and make some heat for which the transformer is not designed.

But you're right the secondary, before its imminent failure, will produce an AC waveform though likely to be a very distorted sine wave.

At half the frequency..

The transformer will saturate and burn out

No.

The waveform across the transformer is still 50Hz.

I presume the confusion is over full vs half-wave rectification regarding ripple frequency, 50 vs 100Hz (60 vs 120Hz)

It's not a guarantee.

Small transformers are very lossy and have a high resistance and may survive the impose DC voltage. Larger transformer with lower winding resistance may not. We also don't know the spec of the transformer the OP had in mind and the applied voltage.

No, at the same frequency

Correct.

I thought current always flowed the same way in primary and secondary.... You know, phases and all that.

Assume a loaded bifilar transformer, both dots up, and draw the winding currents.

The reason that loading a transformer doesn't make it saturate is because the primary excitation flux and the flux from the secondary load current cancel. Loading a transformer reduces the core flux.