# What if a thicker wire is used in the secondary of a step-up transformer?

An n:1 transformer receives a current at its primary and outputs an output voltage

V(out)=V(in)*n and an output current I(out)=I(in)/n

The output power P(out)=V(out)*I(out)=P(in) as expected by the law of conservation of energy.

My question is rather is it necessary to use a thinner (hence narrower cross-section) wire at the secondary so that the transformer works properly? The issue as I understand it, the thinner wire supports a smaller current I(out), but has a longer portion within the magnetic field of the iron core (hence longer or more windings). The electrons are therefore excited over a longer stretch of wire, reach a higher energy level, giving a higher V(out). All of this as expected by conservation of energy laws.

Now, what happens if we used a secondary winding with wire of equal thickness as that of the primary? Which effects will be observed?

• The secondary will excite a greater number of electrons and will yield an output voltage identical to that of the primary because the energy was dispersed among more electrons. It will behave like a 1:1 transformer instead

• The secondary will follow the n*voltage and Amperage/n just like a regular n:1 transformer, but will have the advantage of a lower wire resistance at the secondary (because of the thicker wire)

• Will cause excess current to flow in the primary and overheat the primary windings and eventually cause damage

• Will yield a lower-than-expected value of n.