Transformers - Why more coils in second coil causes more voltage I am learning about magnetic induction and transformers. 


*

*I have coil1 which uses AC to create an oscillating magnetic field.

*I have coil2 which has a voltage applied to it based on the magnetic
field from coil1.
I just heard that if you have more coils in coil2 (the coil dependent on the oscillating magnetic field) you get a bigger voltage and this seems counter intuitive because:


*

*voltage is based on pressure and that pressure is coming from coil1
so how can it be bigger?

*wouldn't more electrons present in coil2 cause more resistance and
thus make the voltage smaller?
How is it that with more coils you get a bigger voltage?
 A: Expanding on Jan Dvorak's comment:
When you change the magnetic field inside a loop, an emf (electromotive force) will be generated. Now if you have two loops, each of these will experience the same e.m.f. When you put them in series, you have a coil with two loops, or two coils with one loop. No matter which way you look at it the voltage across them should be the same - V + V = 2V.
Notice that this doesn't mean you can get more current: as you pointed out, resistance will go up when you have more turns, but that doesn't matter unless a current is flowing. So the tricky thing here is that more turns in the secondary winding of a transformer will increase the voltage, but not the power.
In fact, the opposite happens. When current is allowed to flow in the secondary winding, it will cause a magnetic field that opposes the magnetic field that caused the current in the first place. If you have more turns, then you only need a little bit of current to create the opposing magnetic field.
So while the voltage goes up with more turns, the current you can generate goes down - not just because of resistance but because of inductance, or the ability of the coil to generate a magnetic field in response to a current.
The net result is that a transformer cannot generate power out of nothing - in fact they usually have efficiency (power conversion factor) well below 100%, which is in part why they get hot when you use them...
