My microwave has multiple power settings, ranging from 500 watts to 1500 watts. My question is how is the power reduced/modulated?
I can think of a few options (but I don't know which one is correct/most common):
Is the microwave constantly switched on and off with different 'duty cycles' (similar to PWM) (different on/off times with longer total 'off time' when the microwave is set to a lower 'power level') in order to create lower power output?
Is the electromagnetic frequency of the photons being emitted by the microwave altered resulting in more or less energy per photon? *
Is the amplitude of the waveform (in other words the amount of photons per second) altered resulting in more total energy per second? *
Have I made any wrong assumptions in the three options listed above? Are all three options above theoretically possible in order to achieve modulation of the microwave's power output? Are any of these options used in a microwave oven in order to handle the modulation, if so which is most common?
According to this forum post photon energy is determined by a photon's electrical frequency and a waveform with same frequency/wavelength and different amplitude has more photons being emitted per second.