I have always found the concept of impedance in an electrical circuit bearing an AC load something of a mystery.
At ‘A’ level it was just handed out ex cathedra but explained very poorly (and certainly not in any physical sense).
Even at University where in my first term (the first term of second year students as I made the mistake of going straight into year two of the four year course – a mistake my university career never really recovered from) I did a pretty intensive course on DC circuits, it was never explained (astrophysicists presumably not needing to know much more).
So I bought Electronics Demystified – not normally the sort of book my inner intellectual snob would even contemplate, but I needed to get up to speed and yet not spent a lot of time on the physics.
The book is indeed somewhat simplistic and very short on any sort of physics-based explanation, but lo-and-behold, in chapter two it explains simply that complex impedance is an electromagnetic effect. Maybe I missed it, but I just do not recall anyone ever pointing this basic point out before. I don’t claim I have a full understanding now, but I do know what is at the core.
I am also left, once again, wondering why we teach magnetism so poorly when plainly it is the equal partner of electricity, which we teach an awful lot about (or, to be fair, we did – this was some years ago!)
- Downloads Digital Electronics Demystified e-book (vcbniun.typepad.com)
- Physics of Circuits and Electricity for Little Kids (pragmaticmom.com)
- Teaching (about) Physics (telescoper.wordpress.com)
- Rewriting quantum chips with a beam of light (eurekalert.org)
- Do electrons erode circuits? (abc.net.au)