A while back, I was microwaving a cigarette that had gotten the cherry wet. About twenty seconds into microwaving the cigarette, it caught fire and my microwave started humming and eventually it shorted the entire circuit. I’m assuming this had something to do with the heat produced by the fire and some soft of safety mechanism; am I right?
Thanks.
Probably not. A microwave oven is just a magetron (a thingy that spins around and makes radio waves), a waveguide (a little tube for the radio waves to go through) and a box, and a little control circuit to keep it all working. The magnetron generates radio waves, which go through the waveguide, and end up in the box where the food is. At that point the microwave oven expects there to be something inside the box to absorb all of the radio waves. If you don’t have anything in there, or you have something small that doesn’t absorb a lot of radio waves (like a cigarette) then the radio waves bounce all around and some of them end up getting reflected back into the waveguide and back to the magnetron. This can damage the magnetron, especially in older microwave ovens.
I think it’s more likely that your microwave oven became unhappy because it was being operated without a load. Your microwave oven is an RF (radio frequency) transmission system. The magnetron produces RF energy at microwave frequencies. The microwaves travel from the magnetron to the cavity that contains the food, where they are absorbed by the food. The magnetron is the source and the food is the load. RF transmitters, like the magnetron, are designed to be operated with a load. The load absorbs the energy produced by the transmitter. Operating a transmitter without a load can damage the transmitter or other equipment in the system. That is why you should put a cup of water in the microwave if you are going to do weird things like fry CDs or dry out cigarettes. The cup of water acts as a load and keeps the magnetron happy.