# Transformers

![](new-transformer.jpg)

The amount of primary and secondary windings dictate how much the voltage changes between the two. 

There are two main types of transformers:

![](transformer-types.jpg)

When there are more turns on the primary winding, that means that the voltage on the secondary winding is lower, but the current is higher, and vice versa. Also this relationshop is linear, so half the amount of turns in the second winding, mean half the amount of voltage and double the amount of current. In formula this means:

$\displaystyle \frac{V_{out}}{V_{in}} = \frac{N_{s}}{N_{p}} = \frac{I_{in}}{I_{out}}$