On Wednesday, November 30, 2016 at 5:23:50 PM UTC-5, micky wrote:
How long does it take a microwave oven to warm up?

YIKES!!

This is a single question with two separate answers.

a) Less than 4 seconds for the magnetron tube to reach full output. There will be a sequence as others have noted: Fan-Start, relay click, magnetron start.

b) Then, it depends. We have a 1,100 watt Panasonic that is very fast-cooking to the point that we are very careful of the setting as even 10 seconds makes a difference. A 500-watt device will provide an entirely different experience.

So, it is a combination of the onset time and the actual power of your microwave that will give you the answer. But what is obvious is that 2 @ 5 seconds is NOT 1 @ 10 seconds. The reality is that a 5-second setting will give ~1~2 seconds of actual full-output heat. 10 seconds will give ~6~9 seconds..

Peter Wieck
Melrose Park, PA