> I just have to be pedantic and say that what you are describing is the very opposite of PWM, which runs at high frequencies (e.g. 30kHz), varying the duty cycle over the tiny slice of time.

Yes, this is correct. What parent is describing is generally referred to as bang-bang control [1].

[1] https://en.m.wikipedia.org/wiki/Bang–bang_control

I disagree. The definition of what is high and what is low frequency depends on what you are comparing.

If you are comparing electric capacitances of electric circuits vs the thermal capacitance of a macroscopic object, 1 Hz might be a high enough frequency for doing pwm.

To be even more pedantic, the grandparent could absolutely be describing PWM - PWM is pulse width modulation - it means that there's a fundamental frequency, and within each cycle the stove is "on" for a period and "off" for the rest. The "on" period length is varied (modulated) based on the power requirement.

What "PWM" doesn't define is the fundamental frequency. It could be 0.1 Hz or 10 MHz. Just because the fundamental frequency is slow doesn't make it not PWM.

Those whines drive me crazy and I’m 34! Do any induction cooktops not have that terrible whine? At least with the duxtop portable induction I had to return it because the whine was so bad.

Which leads to the question : which ones do not have a whine? Does the breville? Or which? It’s not something any reviews I’ve seen talk about

Ah, you're right, thank you! I just reused the words of the parent :D