> have a fair more powerful oven, as mine is a fairly old 700W.
> I've never seen a domestic microwave oven without a
> turntable. The etchant does get hotter at the meniscus , but
The ones without a turntable have what's called a 'stirrer' up the top.
It's just metal fan in front of the magnetron that bounces the waves around.
I've seen exactly one one these.
I'm not sure why domestic oven use rotating turntables (price,
reliability?). I think commercial ovens still have stirrers as it means the
handles on the containers you put in will be in the same spot when you open
the door. Some domestic ovens will rotate the turntable to the 'starting
point' to get the same effect.
Tony