A transformer can be viewed as a converter that can increase voltage and lower current, or vice versa. It only works when using AC.
The transformer is effectively a magnetic circuit. The transformer has two or more coils of wire wrapped about a common core.
The ideal relationship is:
If a transformer has an iron core it will be shown with lines in the centre,
To deal with a transformer in a circuit analysis we need to pay attention to the polarity of the coils, and we may consider the inductance of each coil at times.
Consider the example below, from [Nilsson, pg. 450]. We want to find the power delivered to the 1ohm resistor. We will use the mesh current method,
Next we can solve the remaining three equations and three unknown currents using a matrix approach,
Finally we find the power in the resistor,
