Comment on DIY 4th of July
LifeInMultipleChoice@lemmy.world 3 weeks agoYeah I know it uses waves towards the center but the are throughout the microwave, yet no one questions the holes in the metal siding, which are metal circles. So if arcing was an issue on smooth sutfaces, it should happen there as well.
MotoAsh@lemmy.world 3 weeks ago
Not really. The case should be grounded, so even if it were causing a charge differential in the metal, it’d just make a current to ground (or back to the neutral magnetron pole if it’s not grounded). Although ‘current back to ground’ is likely misstating it, since it’d be an AC induced current that wouldn’t be moving too far and ultimately just heat up the metal in place without electrons doing much more than wobbling about.
Metal in the microwave can create arcs because the metal is surrounded by the microwaves with no conductive path anywhere, so charges can just slosh around more and more as power is applied. Get a large enough charge built up in some area that it has the potential to jump through the air to a less charged place, and bam, arc.
The door works fine because the holes are too small to even let the waves through, so there isn’t a big fluctuating EM field all around it to produce much of any different charge potentials to cause current to flow, so no sloshing charges and no real heating.