Transformers

It is far more efficient to transmit electricity at high voltages (and low currents), but we often require quite small voltages within electronic devices. We achieve these numerous and necessary changes in voltage using transformers.

These slides introduce and explain the function of transformers, with some comment on sources of energy loss and associated design strategies.

Keynote slides

Lenz’s Law and Eddy Currents

According to Faradays law, a changing magnetic field will induce an emf. If the emf flows in a current, another magnetic field will be created (similar to how an electromagnet works). The new field and original field oppose each other – and this is known as Lenz’s law. It is required by the conservation of energy.

The slides explain Lenz’s law, and also discuss the related concept of eddy currents.

Keynote slides

Faraday’s Law and Magnetic Flux

During the 1830’s Michael Faraday was trying to create electricity using magnets (because a connection between electricity and magnetism had been recently discovered). He discovered that a changing magnetic field will induce an EMF into a conductor. This became known as Faraday’s law, and underpins all electrical generators.

These slides discuss Faraday’s law, and also provide an overview of magnetic flux (measured in Webers) and magnetic flux density.

Keynote Slides