The Hall Effect – Discovery & Theory
Electricity is a scientific wonder which many people find hard to understand. When you plug in an electrical appliance, such as a kettle, or a fan, you have electricity delivered to that device. This in turn powers the device, in order for it to work as it is supposed to do. This is something you know and understand, but the actual basis of how it works is hard to fathom.
While electricity might be confusing, it can be measured, e.g. using volts, amps, or watts. Something which is even more complicated to measure is magnetism, e.g. a magnetic field. A magnetic field is used to power an electronic motor, or a compass, for example. Now, how it actually works is all down to a theory known as the Hall Effect.
The Hall Effect was discovered in 1879 by Edwin Hall, while he was studying at Johns Hopkins University in Baltimore, working towards his doctoral degree. Hall worked out the effect and it was considered to be way before it time, meaning that it was never truly understood in the mainstream until much, much later; this was all discovered before the electron was even recognised as a very real thing. Nowadays, however, the Hall Effect plays an important part in measuring the power and size of a magnetic field, which can then be used to inform the power behind a motor, for example.
The Theory of The Hall Effect
As we have already established, these days the Hall Effect is used to measure a magnetic field, and this is done by a Hall Effect probe. The probe gives you important information on the strength of the field in question, as well as producing what is known as a ‘voltage difference’.
When electricity and magnetism work together in tandem they move items, or create power, e.g. in an electric motor, a pair of headphones, or a speaker. The Hall Effect is therefore the measurement of a magnetic field which moves across and through an electronic conductor (e.g. something which will allow electric current to flow through it in several directions), towards an electric current, which is perpendicular to the opposing current. It may sound confusing, but this particular effect works hand in hand with the Lorentz Force. The Lorentz Force is a combination of the magnetic and electric forces, cumulating together at one point. When there is no magnetic field available, the charge follows a straight line, also known as the ‘line of sight’ path, without changing direction. Now, when a magnetic field is present, the path of the current collides with ions and other electrical components, curving the line, and therefore moving the charge to accumulate in a different spot, creating power.
When the Hall Effect was first discovered, it was published under the title of “on a new action of the magnet on electric currents”. At the time, this wasn’t paid too much attention, but these days the effect is used for a variety of different power methods, giving greater scope for energy in modern day appliances and machines.
In order to truly understand the Hall Effect, a visual explanation is usually required. For now however, it is important to recognise that this effect was considered to be far too complicated to really become prevalent at its time of discover. As with most things in life however, its importance was further recognised far in the future. We now have a lot to owe to Edwin Hall himself, proving that electricity, power, and magnetism is something which we may never truly be able to understand completely.