ABSTRACT
This chapter discusses the concept of a magnetic field and the principles of electromagnetic induction, the force on current carrying conductors in magnetic fields and the principles of motors, generators, transformers and moving coil meters. The magnetic field pattern in the space surrounding a permanent magnet can be shown by sprinkling iron filings around it or by means of a compass needle being used to plot the directions of the magnetic field. For a single wire the field pattern is concentric circles centred on the wire. If a right-handed corkscrew is driven along the wire in the direction of the current, then the corkscrew rotates in the direction of the magnetic field. The lines of magnetic flux due to the permanent magnet pass through the soft iron and one can explain the force of attraction as being due to the flux lines trying to shorten themselves.
