Calculate transformer turns?

I'm currently doing my homework and am stuck with a question.

The question is: The charger of a notebook delivers a secondary voltage of 19V. Calculate possible number of turns of the primary coil and secondary coil.

How can I calculate this?

Accept the ideal transformer

Then applies

N1 / N2 = U1 / U2

U1 = mains voltage 230V

U2 = 19V

Ü = translation = 230V / 19V = 12, 1052

Now you can get numbers with the ratio

12.1052 to 1 and thus have the possibilities for the. Number of turns

Thank you

The relationships between the two numbers of turns behave like the voltages.

So: secondary voltage 19 V, primary voltage 230 V (mains voltage at the socket).

Now you could do the primary winding 230 turns and the secondary winding 19 turns. That would be a possible solution, but it is not practical. (I do not want to explain now). P: 2300 Wdg and S: 190 Wdg or P: 1150 and P: 95 or something in this ratio would also be possible.

Feel free to contact me if you have any questions

In principle applies
Primary / Usecondary = nprimary / nsecondary = ü (gear ratio)

So for a given ratio of voltages (e.g. 230V / 19V = ü) the number of turns (almost) can be chosen arbitrarily, if only their relationship to each other is equal to ü.

Incidentally, switching power supplies are used today that do not have a conventional transformer, but a much smaller HF transmitter.

In addition: A charger in a notebook basically supplies DC voltage