Microwave oven - reducing power

Apr 04, 2004 5 Replies

I have my original micorwave oven from about 20 years ago and it still works. To judge by the clicking sounds the lower settings for defrost, simmer, etc seem to work by the meagnetron being switched on and off every 15 seconds or so,



Do modern microwave ovens also use this switching method or do they put our less microwave energy for the lower settings?


Yes. Often you can see the light get slightly dimmer when the magnetron turns on.

-- Richard

Magnetrons have a rather narrow range of operating voltages and hence are basically fixed power output devices, so yes, they still switch them on and off to control the average power.

Jim Pennino Remove -spam-sux to reply.

A friend had a microwave that cycled like that; we could tell because the kitchen lights dimmed and brightened as it cycled. ;-)

Agree. The major difference between older microwave ovens and the newer models is that the newer models control the magnetron duty cycle at a power line frequency rate, much as a light dimmer. (Panasonic calls its implementaton of this technology "Inverter Power Level Control".)

Harry C.

I am not quite clear on what you say.

Do you meant to say that the switching between on & off is done much more frequently in modern microwave ovens? AT perhaps 50 or

60 Hertz?

My old oven switches on & off in approx 20 second intervals.

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