this post was submitted on 21 Oct 2023
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That's true with any electric heater element. It's called pulse width modulation (PWM) and is actually very effective when done properly. Seems like the frequency is too long on yours. It should be cycling many times per second, meaning the full power is only on for milliseconds at a time, nowhere near enough to actually burn things.
Even a cheap Arduino is capable of PWM at 16MHz (16 million duty cycles per second; we're talking microseconds here now). So I'd think even a cheap one should have good PWM control, but I guess you get what you pay for.
I don't know about proper induction cooktops, but the hot plates all seem to use mechanical relays to switch power, so they're limited to far less than 16 MHz. Most seem to use regular, industrial controls that operate at more like 1-0.1 Hz.
I honestly don't think you'd want to use anything but a mechanical relay to switch 10-15 amps. Do that with a solid state relay, and you're going to waste 15-25 W in a small package that will have to be radiated somewhere.
I read a bunch of reviews from reputable sites and bought what they said was the best. Apparently they couldn’t even spring for an Arduino because the pulse widths are seconds long.
It's not the logic that's expensive, it's the solid state relay suitable for high power, high frequency switching
I don’t need MHz switching. A few kHz would be better than just turning it on for 1 second out of 10 for “low power.”
Still can't do it with a cheap SSR or a mechanical relay
By "expensive" we're still only talking a dollar or two. It's not going to spike their cost to the point where it would be prohibitive to them.