John Robertson wrote on 12/12/2017 11:12 AM:
On 2017/12/12 6:14 AM, James Wilkinson Sword wrote:
On Tue, 12 Dec 2017 03:49:55 -0000, rickman wrote:

James Wilkinson Sword wrote on 12/11/2017 11:50 AM:
On Mon, 11 Dec 2017 04:07:43 -0000, Mary-Jane Rottencrotch
wrote:

On 2007-01-19 12:13, Peter ****er wrote:
Is it really true that turning on a microwave with nothing in it will
break it?

Derp.

It was a sensible question. This could be done by accident.

I interviewed with a place once that was doing something with testing
microwave ovens. They ran them all the time with nothing in them. I had
always read that you should not operate them with nothing to absorb the
energy and mentioned that. I got a strange look from the guy. Obviously
the energy that would be absorbed is within the limits of what the ovens
were designed to get rid of.

It seems nothing happens, well no fire or explosion anyway. He never said
if it still worked afterwards:
https://youtu.be/AsaW5xnOkCA


Why don't you simply put a load meter on the microwave and try running it
empty or with a cup of water. I expect that with no load the unit will
simply not draw as much current.

I don't think a microwave works like a transformer. The energy is emitted
by the unit like an antenna regardless of whether there is something to
absorb it or not. The difference is with a radio antenna the energy is free
to leave the transmitter into free space. A microwave is in a sealed box.

Hmmm... maybe the waves do go back into the klystron and reduce the power
drawn. Then why would the makers have warned to not run them empty?


Do regular ovens 'care' if something is in them or not? Why should a microwave?

Because they aren't the same?

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998