What is a magnetic circuit?
All magnetism flows from north to south, and a magnetic circuit is the journey it takes to get from north to south.
The magnetism is usually generated by permanent magnets or electromagnets and travels along magnetic paths within the circuit. The circuit may also contain one or more "air gaps" filled with nonmagnetic material. Magnetic circuits are used in devices such as motors, generators and transformers as an efficient way to channel magnetic fields.