I warn this question can hurt some sensibilities as my knowledge of electric current are near zero Is there something equivalent to a transformer for voltage reduction for DC current? I mean something with primary and secundary bobbins and using magn induction. Is it done in DC with...

A beginner question eletronic wise: I assume voltages differences between line out and phone out are not very big. I usually can drive my hp or external speakers from one or the other, then... why they put those two "outs"? Appart from voltage, what is the difference between phone and line...

I'm curious about that little speakers. Are they worthwhile? I've done a search here and it seems nobody has talked about it yet (what is surprising, as people has talked about almost any thing imaginable in these forums! ) Sometimes I miss a very small near field speaker system, portable...