Electrical and Magnetic 'circuits'
Although it might seem either odd or contrived, it is often helpful to consider electromagnetic setups as being like electrical circuits. The magnetic flux (field lines) can be thought of as 'flowing' through Iron cores, for example, being 'driven' by current-carrying coils, in a similar way to electrons flowing through a resistor, driven by a cell. Of course, magnetic flux doesn't actually move (despite its name), but it's often helpful to think of it as if it is.
You can then show that there are exact magnetic equivalents of (hopefully) more familiar quantities from electrical circuits, such as resistance, current, PD and so on. Here's a sheet which summarises them: