Something that I’ve noticed across most of the microwave ovens that I’ve used is that when they hum while cooking food, I can pick out 2 distinct tones. One of them is pretty clearly 60 120 hz, the 2nd harmonic of the AC power frequency. The other is consistently a minor 7th above that (which would be somewhere around 106-108 212-214 hz depending on the exact ratio). What causes this 2nd frequency to be produced?

Edit: after checking against a tone generator, the low frequency is actually 120 hz, double the grid frequency. The question is still the same, just an octave higher.

  • accideath@lemmy.world
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    11 months ago

    Yup, also primarily use it for reheating food. Sometimes, when I’m lazy and just want sth to eat, I’ll make myself microwave potatoes. And I also use it to defrost frozen vegetables or fruit sometimes.

    However, when I was living in a one bedroom apartment, which didn’t have an oven in the kitchen-corner, I had a microwave with integrated oven and with that I was able to bake myself anything that fits into a pizza sized round baking tray. Still love that thing. It’s a 30 y/o hand me down Siemens from my uncle that still works perfectly. It’s also rather large (about twice the size of a normal microwave) and sadly doesn’t fit into my current kitchen…