"ms_peacock" > wrote:
> I've had numerous electric stoves over the years and the elements don't go
> on and off on any of them. They already use a "dimmer switch." The heat
> is constant at whatever setting you put the dial.
>
> I had one stove that had an element that was thermostatically controlled
> and it did vary the heat. But it didn't just go off and on, as the temp
> of the food came up the element would lower the heat output to maintain
> the temp. I still miss that stove, it also had an oven and a half.

In reality, those electric stoves were going on and off the whole time, and
you never noticed! If you have a very quiet kitchen and you listen very
carefully, you can hear the switch turn the burner off and on. The "dimmer
switch" is adjusting how long the "on" time is versus the "off" time. The
owner's manual on my 1982 GE electric range even mentioned the noise the
switch made in the troubleshooting section, to put to rest the minds of
people who noticed the sound.

Even dimmer switches for lights are in a way turning the light on and off to
adjust the light intensity. The dimmer switch is varying the amount of time
the light bulb filament is turned on versus turned off. Only it is happening
60 times a second versus every several seconds as on an electric stove
burner. The principle is basically the same, but on dimmers the controls are
solid state electronics, while on a stove burner the controls are
mechanical. It would be costly to make a solid state electronic control to
handle the power required for a surface burner. Most light dimmers are 300
watts capacity. A surface burner is about 2,500 watts.

This cycling of the burner is different than thermostatic control. What it
is doing is keeping the burner on for a percentage of the total time, giving
a proportional heat output, regardless of how hot the pan ends up getting.
There are thermostatically controlled surface burners out there, but they
are not that common.