[The Twelfth Blog] Magnetism.

I wouldn't consider myself a very curious person, naturally, so I have probably never thought about it (although I don't think I would have noticed in the first place... :|), but after this lesson in physics, I know why so many different objects can be powered/charged by being plugged into wall outlets. It can't be that all objects require the same voltage, right? So there must be something that is able to convert the wall outlet's 120 volts into the proper voltage for each individual appliance... And this trusty tool is the AC adaptor! These are so common that many people probably don't even think about them. In fact, I'm making use of one right now, as I charge my laptop whilst writing this blog.


How it works: 
- Within the adaptor, there is a ferromagnetic core (say of iron) around which two coils (primary and secondary) are wound
- The primary coil receives the alternating current from the wall outlet, which creates an alternating magnetic flux 
- This alternating magnetic flux leads to a varying magnetic field in the iron core
- When the secondary coil is brought within the varying magnetic field, an alternating current is induced within it
- Since V₁/N₁ = V₂/N₂, V₂ is determined by the ratio of the primary coil's loops to the secondary coil's loops
- To reduce the voltage that leaves the adaptor, the secondary coil should be made of fewer loops accordingly


Well we sure do seem to learn new things every day, even things that we may never have thought about if not for physics class. :]