EMP would fry the energi sourse e.g. the battery but magic screw with the wiering.

Arcanum offers a great explanation for that (copy-paste): Technology is based around understanding and working within natural laws, such as using knowledge of chemistry to produce gunpowder. Magick is centered around distorting and bending those laws to allow unnatural events to occur, such as generating a lightning bolt to strike a location when the two areas have nowhere near the potential difference necessary to do so. As such, a mage is a person who is adept at generating a distortion field, or an area within which physical principles can be violated. When a distortion field intersects a technological device, that device is liable to fail as the principles upon which it is based may cease to behave predictably. Similarly, technology defuses distortion fields, as the more physical or mathematical principles which come into play in a given instance there are, the more distortion is necessary to circumvent them. Therefore, a highly skilled technologist will be greatly hindered in any usage he attempts of magick or magickal items, because he will invariably expect them to work based on predictable, easily definable principles. Similarly, any powerful mage who attempts to wield complex technology is likely to have it backfire as the distortion field centred around him will interfere with the functioning of its many mechanisms in a statistical way.

 

For my own conveniance, and cause I want to have soemthing different, I'm Using something that is, in my opinion, something very different.

A crude analogy:
The effects of a wire carrying current differ with changes in frame: in some kinds it can be seen as purely electric, in others purely magnetic. But basically, they're all the exponent of the same phenomenon: movement of electrons.

So, magic will have it’s basic upon some, not all, physical laws. It also, of course, follows some of its own.

@Styx
The thing about violating physical principles is, if you violate one, then they would genrally have a butterfuly affect and cause a lot more of em to disturbed.
For example, if A and B do not have enough potential to cause a lighting bolt, where do the electrons that make up this bolt come from? Magic can't just "create" mass out of nothing. That would violate the most Basic of all laws.
Etc etc.

 

Conjuring can create temporary items and as with a lightning bolt it creates just electrons the A to B is just the targeting of magic or else youd just fry yourself. After the bolt strikes the electrons disappear like any other conjured item.

Magic is more about bending and circumventing the principles. And as to the butterfly effect, well who said magic was logical.

Ps:As noted the Arcanum rule is copied from an external source and doesnt completely apply to the Potter-verse. And i would like to note that electricity was brought up as just an analog.

 

I always thought of magic as incredibly high frequency energy waves up in the radiation zone. But it was the way these waves were handled that makes them safe or dangerous. We use radiation to treat cancer but also know that miss use of it can cause great damage. Maybe wizards are just people who can create high frequency energy waves are manipulate them to various uses. Thus visible light in spells is just energy burning off the spells and dropping into the lower frequency range which can be seen by the human eye. Thus it would also put out waves that fall into the radio wave frequency.