I am trying to understand the datasheet of a small transformer (SMT transformer, ref B82801B from EPCOS, available for example here: https://www.elfadistrelec.no/Web/Downloads/_t/ds/B82801B_eng_tds.pdf?mime=application%2Fpdf ).
I am not an electrical engineer, and here is my understanding of how a transformer works (I write this here as it influences how I read the datasheet). There is a primary, resistance \$R_1\$ and inductance \$L_1\$, and a secondary, resistance \$R_2\$ and inductance \$L_2\$. Considering perfect coupling between those, the coupling coefficient is M = \$ \sqrt{L_1 L_2} \$. Therefore, I expect that the transformer follows equations (with \$V\$ and \$I\$ tension and intensity, and index indicates primary / secondary):
\$ V_1 = R_1 I_1 + L_1 \frac{d I_1}{dt} + M \frac{d I_2}{dt}\$,
and symmetric formula for \$V_2\$ (the sign before M may vary, depending on how the transformer is wired).
When I look in the datasheet page 3, I get to know which pins are to the primary and secondary coils. This is great, I think I get it right.
When I look at the datasheet page 5, I get:
The turn ratio. This is great, I understand (it will give me amplification if no load).
The typical max DC resistance \$R_i\$ for the primary and secondary. This is great, and I get the right value when I measure with the multimeter.
A \$L_{min}\$ value. What is that? Is it \$L_1\$, \$L_2\$, or \$M\$? Comparing the scaling of \$L_{min}\$ with the number of turns in the secondary, it looks like \$L_{min} \propto N_2^2\$, so I would guess actually \$L_{min}\ = L_2\$ as in general for a coil, \$L \propto N^2\$. Am I right?
What is Voltage-Time product? I guess it is maximum value of (Voltage) * (time when applied), am I right?
Why is there a recommended \$R_T\$?