When electrical items are made, the manufacturers put magic smoke inside them. This is what makes them work.
If you abuse electrical items (overload, excess supply voltage, incorrect polarity etc.), the magic smoke will come out. Usually you will see the smoke, sometimes you only smell it. Either way, it means the smoke has escaped.
Once the magic smoke has escaped, the item will not work any more. This is clear proof that the smoke is necessary for the item to function.
Do I dare ask what happened for a wize wizard such as yourself to suddenly reveal a dark arts secret?
I think itās all this recent talk of old computers. They donāt necessarily conform to modern standards, and there are things the current engineering courses donāt teach any more. 
I have one corner in my basement that is dedicated to smokeless electronics. It is a very sad corner.
Yes, there are considerable similarities. But whilst Phlogiston is a mundane substance, and can be explained by Aristotelian four-element theory (fire, air, hot, light), magic smoke is, of course, a magical substance. It can only be explained in terms of Hermetic and Enochian theory, and by reference to the Grand Arcana.
In this respect, it has much in common with quantum physics.
Yes of course! A close relative to Thaumium.
Channelling Pratchett by way of Charles Stross.
I confused
Sometimes electrical items will cease to work even when no magic smoke is seen or smelled. Is this because the smoke has lost its magic, simply vanished, or something of that nature? I want to go into electrical engineering but still do not have a firm grasp on the fundamentals of magic smoke.
You must bear in mind that this is only a basic primer for technicians.
There are several reasons electrical items may fail, loss of magic smoke being only one of them. Electrical goods are also known to fail through perversity and ill-will. You must also take into account the effect of Murphyās Law - āIf something can go wrong, it willā.
Unfortunately, the workings and creation of magic smoke are beyond the scope of this little tutorial. The discipline is a subject best suited to postgraduate study. I understand Arkham University offer some excellent courses.
I think the unseen university in ankh morpork could help with a description of the āthaumāā¦
This is why a good thwack, can set them right again?
Yes, electricity is taciturn and bad-tempered. Firm discipline often helps. Donāt try it with lightning, though.
If you attempt to discipline lightning as @Sir_oops suggests, by giving it a āgood thwackā, you are likely to discover one of the ways magic smoke is made.
Sadly, those who create magic smoke in this manner are seldom able to make any use of it.
I always assumed I was re-aligning the electrons, but if I follow what you are getting at, electrons have little to do with it?
The trouble with magic smoke, is that the uncertainty principle comes into play. As I donāt know my ar5e from my elbow, I find myself sitting around all day on my elbowsā¦magic smoke has the same properties I thinkā¦
Electrons are certainly involved, but only because they are charge carriers. Charge is a fundamental property, but ultimately derived from quarks. And the thing to remember about quarks is that very few of them have charm. The rest haveā¦ something elseā¦
While you are sitting around on your elbows, you may notice a dead cat walking past. In theory, if you do not notice the cat, it will remain both dead and alive. If you do notice it, it will immediately become either alive or dead. Unfortunately, the eminent Mr Schrodinger, who first described this phenomenon, failed to account for the fact that cats have nine lives. This greatly complicates the situation.
From this we learn that the mere act of observation can influence a situation.
To illustrate the unfortunate consequences of ignoring the properties of charge, it is perhaps worthwhile to recall the famous experiments of the Przeslawski twins in Krakow, Poland, in 1884.
In an attempt to summon electrical demons, and using an enormous version of the newly developed Wimshurst machine, the brothers managed to induce a massive, identical, static charge in both their bodies.
The resultant forces threw the two brothers apart with such vigour that they smashed through opposite walls of their laboratory. Needless to say, this was the end of their scientific careers. The event did, however, give rise to the well-known maxim āLike Poles Repelā.
This is the best description of this fundamental law of electricity that I have ever read in my life. ever.
