We know from the books that magic interferes with electronics, but what is not explained is what kind of devices are affected and the range at which magic can affect electronics.

The first question: Does magic interfere with anything that uses electricity, or only more advanced gadgets with microchips and the like?

Now, I don't expect a mobile phone or a digital camera to work in Hogwarts, but what about simple electronic devices that do no "thinking"? Could a torch (flashlight) work in Hogwarts or Diagon Alley? What about a car engine, since it still needs electrical shocks from spark plugs to detonate the fuel-air mixture in each cylinder?

We know that lightning still occurs around Hogwarts, so magic and electricity should not be mutually exclusive. This leads me to believe that very simple electronics should still work fine. What does everyone else think?

And question two: At what distance does magic start messing with electronics?

Canon seems to contradict itself when it comes to the range at which magic messes with electricity. Hogwarts, which has a high concentration of magic, supposedly makes electronic gadgets go haywire anywhere within the grounds. Yet the similarly very magical Diagon Alley is hidden right in the middle of London! If magic interferes with electronics, then shouldn't all of the telephones and televisions, and even cars not work in the adjacent areas? Since there is no evidence for this, do we then assume that electronics have to be within an absurdly close distance of even ultra-concentrated magic to start malfunctioning?

Tim the Enchanter