On Feb 14, 1:07 am, (Dave Martindale) wrote:

....

The "infinite heat" stove controls have simple mechanical switches that
are either on or off. They have no effect on power waveform (unlike
triac dimmers).

That depends on what you mean by "no effect" ---

They chop the AC sinusoidal waveform to turn power off and on.
Whether they do it randomly in the cycle or as w/ diac/triac switches
at or very near the crossing voltage makes some difference in what the
resulting waveform is, but in either case the output isn't continuous
and is a chopped sine. The "more expensive" triac dimmers mentioned
earlier have some additional components (usually an RC to introduce a
time delay tied into another diode to bleed the cap while the main
triac isn't conducting to contribute a portion during the "off"
cycle. For incandescent lights, it reduces flicker and "singing"
caused by the harmonics generated in the simple "bang-bang" chopped
control case.

For the heater, (and the cooktop range element) the resulting
difference in input waveform would be pretty much immaterial owing to
the higher thermal mass as compared to a bulb filament and the
likelihood of objectionable generated mechanical vibration is much
less again owing to the size/mass.

If, otoh, by no effect you meant "the power waveform is just a
sinusoid with some variable fraction missing" referring to there being
no attempt to compensate, then I agree. Wasn't sure which
interpretation you were intending...

Hopefully, that will help Paul more than confuse further.