Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001

4.1 TRANSFORMERS

 

· 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,